Richard Boydell suffered from cerebral palsy and acquired language as a child through listening and reading alone. His first attempt at communication was at age 30, with the aid of a typewriter. He later became a computer programmer. A short excerpt from a computer-related book:
"Richard Boydell was born with a first-class brain, indomitable and resourceful
parents, ... He was born in 1933 with severe jaundice and cerebral palsy, ..."
Richard Boydell:
"I acquired an understanding of language by listening to those around me. Later, thanks to my mother's tireless, patient work I began learning to read and so became familiar with written as well as spoken language. As my interest developed, particularly in the field of science, I read books and listened to educational programs on radio and, later, television which were at a level that was normal, or sometimes rather above, for my age. Also when people visited us ... I enjoyed listening to the conversation even though I could only play a passive role and could not take an active part in any discussion ... As well as reading books and listening to radio and television .... I read the newspaper every day to keep in touch with current events".
Stephen Krashen "The Input Hypothesis: Issues and Implications" (1985), citing Adrian Fourcin's 1975 article "Visual feedback and the acquisition of intonation".
Fourcin's article is also mentioned in "Foundations of language development" by Elizabeth Lenneberg (1975). Also mentioned in "Language development in exceptional circumstances" by Dorothy Bishop and Kay Mogford.
According to Fourcin, Boydell's writing was "elegantly phrased" although he had never written anything before. Krashen believes that Boydell's ability to express himself was due to his listening and reading and he uses this as an example for his input hypothesis.
Krashen uses Boydell as an argument against the "comprehensible output" theory.
Anyone seeking parallels with adults trying to learn a foreign language through passive exposure should keep in mind that Boydell learned English as a child. English was his mother tongue. Native speakers use the language internally, during abstract reasoning and problem solving. How often we actually "think" in our mother tongue is a separate issue but internal use of language is definitely a native speaker characteristic. A passive adult consuming foreign entertainment will not behave as a child acquiring his mother tongue. Advanced speakers of a foreign language would most likely start using their new language internally only after a prolonged period of habitual daily language production and interaction with native speakers. Another issue is that Boydell could speak only with extreme difficulty due to cerebral palsy. His writing was impeccable, but I cannot find any information about his spoken language skills.
Sunday, August 16, 2009
Friday, August 14, 2009
Language and the Brain
The language loop is found in the left hemisphere in about 90% of right-handed persons and 70% of left-handed persons, language being one of the functions that is performed asymmetrically in the brain. Surprisingly, this loop is also found at the same location in deaf persons who use sign language. about.com
“Production of Oral or Written Language. Normal spontaneous speech begins with the intent to communicate followed by the internal organization of the thought, access to the words to be used in expressing the thought or idea and their phonetic representations (word sounds), the initiation of the intention, and finally the actual production (articulation) of speech. Spontaneous writing makes similar demands, except rather than requiring the external articulation of phonemes, the phonemes are converted into written symbols (graphemes). In typical dominance patterns, most of these language functions are mediated primarily by the left hemisphere. Whether the left, right, or both hemispheres are “responsible” for the intent to communicate is unclear. However the failure to initiate spontaneous communication typically has been associated with left anterior (frontal) lesions.
Language Reproduction. In contrast to language production, language reproduction, in its broadest sense, refers to the ability to reproduce language in either the same or alternate form from which it was perceived. Typically when we think of this aspect of language, we think of the repetition of spoken language or the transcription of spoken or written language. However, reading aloud (as opposed to silent reading for comprehension) also may be considered language reproduction.
Word-finding ability. The ability to associate a “word” with either an internal (thought or recollection) or external (perception) representation of an object or idea is a fundamental function of language. Creating these associations (i.e. words) and then retrieving them, either spontaneously or on cue, appear to be skills relegated to the left hemisphere…
Word recognition. In addition to being able to retrieve a word when needed (verbal expression), linguistic communication also demands that when a word is perceived, either aurally (auditory comprehension) or visually (reading comprehension), its meaning and/or associations are understood (verbal comprehension). Language comprehension may be broken down further into its semantic and syntactic components.
While the left hemisphere clearly is dominant for comprehending both semantics and syntax, again in split-brain studies the right hemisphere has been shown to have some limited semantic capacity and even more limited ability to process syntax independent of the left hemisphere. However, somewhat paradoxically, in the presence of an intact left hemisphere, right hemispheric damage may lead to significant difficulties in appreciating subtle or thematic aspects of communication, especially when metaphors or sarcasm are employed.
Internal use of language. Language not only is used for communicating with others, it also is used internally. It serves as an important base for abstract reasoning and problem solving. While both hemispheres contribute to the development of new and creative insights into the world around us, many of the problems presented to us on a day-to-day basis are represented in verbal terms. Even if not, we often try to assign words to our ideas, motivations, imaginings, and conflicts in order to analyze, manipulate, and weigh their various permutations and potential outcomes. Strictly speaking, what we define as rational thought and abstractive capacities appear to be the application of formal linguistic principles to a particular problem. Again, while the split-brain work has suggested that the right hemisphere certainly is capable of problem solving and decision making (in certain circumstances, apparently even more efficiently than the left hemisphere), it appears that it is the left hemisphere that mediates such thought processes in most individuals.”
Clinical Neuroanatomy by John Mendoza, Anne L. Foundas p. 346
Functions of different parts of the cortex (according to the Wernicke-Geschwind model)
Reading
Reading aloud. Written language is received by the visual cortex and transmitted to the angular gyrus. The signal is then sent to Broca’s area and the adjacent motor complex for articulation.
Silent reading involves the visual cortex, the angular gyrus, Wernicke’s area and Broca’s area.
The angular gyrus receives the visual information from the visual cortex and recodes it into auditory form and then transmits it to Wernicke’s area for interpretation.
Speech production The signal moves from Wernicke’s area to Broca’s area which then transmits it to the motor complex. Obviously spontanous speech production is a lot more than that. This space reserved for a good explanation.
Listening
Passive listening.
“During passive listening, activation is almost exclusively limited to the superior temporal areas, possibly due to the fact that no language output (naming) is being required. Sound stimuli that require little or no linguistic analysis, such as noise, pure tones, and passive listening to uninteresting text, produce nearly symmetrical activity in or around the superior temporal gyrus of each hemisphere (Binder et al. 1994). When the task requires listening for comprehension, significant lateralization to the language-dominant hemisphere is present (Schlosser et al. 1998.)
Stimuli of higher presentation rates or greater difficulty produce greater activation. When words are presented too slowly, allowing time for the subject to daydream between stimuli, activation is greatly reduced. Tasks that are uninteresting, although “language rich” may produce activation of primary auditory areas but little activation of language areas. Stimuli that are challenging or interesting produce greater activation.”
Audiology by Ross J. Roeser, Michael Valente, Holly Hosford-Dunn
Active listening
“Brain regions specifically implicated in listening to the spoken word (active listening) have been identified on MRI scans by subtracting the signal from regions (such as auditory cortex) that are engaged when listening to random tones (passive listening) from the total signal produced by listening to speech.
Listening to speech activates:
“Wernicke’s area on the left side, which is thought to permit discrimination of verbal from non-verbal material; The angular gyrus which identifies phonemes; The middle temporal gyrus which identifies phonemes; The middle temporal gyrus (area 21) and area 37 identify words from phoneme strings and tap into semantic networks located in the left dorsolateral preffontal cortex (areas 9 and 46), that must be searched to traduce the meaning of speech; Broca’s area is activated, because when listening to speech we covertly rehearse the articulatory commands needed to pronounce the words, a process referred to as subvocal articulation.”
Neuroscience by Alan Longstaff
Reading
“Clearly reading requires visual processing. Subsequently, in novice readers, the parieto-temporal region (angular gyrus and Wernicke’s area) dismantles words into phonemes so that they can be identified. However, in experienced readers the extra-striate occipito-temporal cortex (area 19) recognizes entire words instantly. Activation of a network that links the supramarginal gyrus (area 40), and area 37, to the anterior part of the Broca’s area (area 45), via the insula, allows access to semantic networks in the dorsolateral prefrontal cortex so that the meaning and pronunciation of the words can be retrieved. Finally, either subvocal articulation or reading aloud is accompanied by activation of the whole of Broca’s area, the medial supplementary motor area (area 6), motor areas subserving face and tongue (area 4), and the contralateral cerebellar hemisphere.”
Neuroscience by Alan Longstaff
The Wernicke-Geschwind model
“Norman Geschwind assembled these clues into an explanation how we use language. When you read aloud, the words (1) register in the visual area, (2) are relayed to the angular gyrus that transforms the words into an auditory code that is (3) received and understood in the nearby Wernicke’s area and (4) sent to Broca’s area, which (5) controls the motor complex, creating the pronounced word. Damage to the angular gyrus leaves the person able to speak and understand but unable to read. Damage to Wernicke’s area disrupts understanding. (Comment: Reading, both aloud and for comprehension, is usually impaired in Wernicke's aphasia.) Damage to Broca’s area disrupts speaking (Comment: often also reading aloud).
The general principle bears repeating: complex abilities result from the intricate coordination of many brain areas. Said another way, the brain operates by dividing its mental functions – speaking, perceiving, thinking, remembering – into subfunctions. Our conscious experience seems indivisible. The brain computes the word’s form, sound, and meaning using different neural networks… To sum up, the mind’s subsystems are localized in particular brain regions, yet the brain acts as a unified whole.”
Psychology, Seventh Edition in Modules
by David G. Myers
A critique of the Wernicke-Geschwind model
“PET studies have revealed that because visual linguistic stimuli are not transformed into an auditory representation, visual and auditory linguistic stimuli are processed independently by modality-specific pathways that have independent access to Broca's area. Moreover, because the linguistic processing of visual stimuli can bypass Wernicke's area altogether, other brain regions must be involved with storing the meaning of words (Mayeux & Kandel, 1991,p. 845; also see Kolb & Whishaw, 1990, pp. 582-583). Thus, not only do there seem to be separate -- parallel -- pathways for processing the phonological and semantic aspects of language, language processing clearly involves a larger number of areas and a more complex set of interconnections than just those identified by the W-G model (Wernicke-Geschwind model) (Mayeux & Kandel, 1991, p. 845). Indeed, the PET studies support the notion that language production and comprehension involve processing along multiple routes, not just one:
No one area of the brain is devoted to a very complex function, such as 'syntax' or 'semantics'. Rather, any task or function utilizes a set of brain areas that form an interconnected, parallel, and distributed hierarchy. Each area within the hierarchy makes a specific contribution to the performance of the task. (Fiez & Petersen, 1993, 287)."
Using Pet Toward A Naturalized Model Of Human Language Processing
By Robert S. Stufflebeam
Active reading
“Recall that according to Wernicke both visual and auditory information are transformed into a shared auditory representation of language. This information is then conveyed to Wernicke’s area, where it becomes associated with meaning before being transformed in Broca’s area into output as written or spoken language…Using PET imaging, they determined how individual words are coded in the brain when the words are read or heard. They found that when words are heard, Wernicke’s area becomes active, but when words are seen but not heard or spoken, there is no activation of Wernicke’s area. The visual information from the occipital cortex appears to be conveyed directly to Broca’s area without first being transformed into an auditory representation in the posterior temporal cortex.”
Essentials of neural science and behavior by Eric R. Kandel, James Harris Schwartz, Thomas M. Jessell
“Production of Oral or Written Language. Normal spontaneous speech begins with the intent to communicate followed by the internal organization of the thought, access to the words to be used in expressing the thought or idea and their phonetic representations (word sounds), the initiation of the intention, and finally the actual production (articulation) of speech. Spontaneous writing makes similar demands, except rather than requiring the external articulation of phonemes, the phonemes are converted into written symbols (graphemes). In typical dominance patterns, most of these language functions are mediated primarily by the left hemisphere. Whether the left, right, or both hemispheres are “responsible” for the intent to communicate is unclear. However the failure to initiate spontaneous communication typically has been associated with left anterior (frontal) lesions.
Language Reproduction. In contrast to language production, language reproduction, in its broadest sense, refers to the ability to reproduce language in either the same or alternate form from which it was perceived. Typically when we think of this aspect of language, we think of the repetition of spoken language or the transcription of spoken or written language. However, reading aloud (as opposed to silent reading for comprehension) also may be considered language reproduction.
Word-finding ability. The ability to associate a “word” with either an internal (thought or recollection) or external (perception) representation of an object or idea is a fundamental function of language. Creating these associations (i.e. words) and then retrieving them, either spontaneously or on cue, appear to be skills relegated to the left hemisphere…
Word recognition. In addition to being able to retrieve a word when needed (verbal expression), linguistic communication also demands that when a word is perceived, either aurally (auditory comprehension) or visually (reading comprehension), its meaning and/or associations are understood (verbal comprehension). Language comprehension may be broken down further into its semantic and syntactic components.
While the left hemisphere clearly is dominant for comprehending both semantics and syntax, again in split-brain studies the right hemisphere has been shown to have some limited semantic capacity and even more limited ability to process syntax independent of the left hemisphere. However, somewhat paradoxically, in the presence of an intact left hemisphere, right hemispheric damage may lead to significant difficulties in appreciating subtle or thematic aspects of communication, especially when metaphors or sarcasm are employed.
Internal use of language. Language not only is used for communicating with others, it also is used internally. It serves as an important base for abstract reasoning and problem solving. While both hemispheres contribute to the development of new and creative insights into the world around us, many of the problems presented to us on a day-to-day basis are represented in verbal terms. Even if not, we often try to assign words to our ideas, motivations, imaginings, and conflicts in order to analyze, manipulate, and weigh their various permutations and potential outcomes. Strictly speaking, what we define as rational thought and abstractive capacities appear to be the application of formal linguistic principles to a particular problem. Again, while the split-brain work has suggested that the right hemisphere certainly is capable of problem solving and decision making (in certain circumstances, apparently even more efficiently than the left hemisphere), it appears that it is the left hemisphere that mediates such thought processes in most individuals.”
Clinical Neuroanatomy by John Mendoza, Anne L. Foundas p. 346
Functions of different parts of the cortex (according to the Wernicke-Geschwind model)
Reading
Reading aloud. Written language is received by the visual cortex and transmitted to the angular gyrus. The signal is then sent to Broca’s area and the adjacent motor complex for articulation.
Silent reading involves the visual cortex, the angular gyrus, Wernicke’s area and Broca’s area.
The angular gyrus receives the visual information from the visual cortex and recodes it into auditory form and then transmits it to Wernicke’s area for interpretation.
Speech production The signal moves from Wernicke’s area to Broca’s area which then transmits it to the motor complex. Obviously spontanous speech production is a lot more than that. This space reserved for a good explanation.
Listening
Passive listening.
“During passive listening, activation is almost exclusively limited to the superior temporal areas, possibly due to the fact that no language output (naming) is being required. Sound stimuli that require little or no linguistic analysis, such as noise, pure tones, and passive listening to uninteresting text, produce nearly symmetrical activity in or around the superior temporal gyrus of each hemisphere (Binder et al. 1994). When the task requires listening for comprehension, significant lateralization to the language-dominant hemisphere is present (Schlosser et al. 1998.)
Stimuli of higher presentation rates or greater difficulty produce greater activation. When words are presented too slowly, allowing time for the subject to daydream between stimuli, activation is greatly reduced. Tasks that are uninteresting, although “language rich” may produce activation of primary auditory areas but little activation of language areas. Stimuli that are challenging or interesting produce greater activation.”
Audiology by Ross J. Roeser, Michael Valente, Holly Hosford-Dunn
Active listening
“Brain regions specifically implicated in listening to the spoken word (active listening) have been identified on MRI scans by subtracting the signal from regions (such as auditory cortex) that are engaged when listening to random tones (passive listening) from the total signal produced by listening to speech.
Listening to speech activates:
“Wernicke’s area on the left side, which is thought to permit discrimination of verbal from non-verbal material; The angular gyrus which identifies phonemes; The middle temporal gyrus which identifies phonemes; The middle temporal gyrus (area 21) and area 37 identify words from phoneme strings and tap into semantic networks located in the left dorsolateral preffontal cortex (areas 9 and 46), that must be searched to traduce the meaning of speech; Broca’s area is activated, because when listening to speech we covertly rehearse the articulatory commands needed to pronounce the words, a process referred to as subvocal articulation.”
Neuroscience by Alan Longstaff
Reading
“Clearly reading requires visual processing. Subsequently, in novice readers, the parieto-temporal region (angular gyrus and Wernicke’s area) dismantles words into phonemes so that they can be identified. However, in experienced readers the extra-striate occipito-temporal cortex (area 19) recognizes entire words instantly. Activation of a network that links the supramarginal gyrus (area 40), and area 37, to the anterior part of the Broca’s area (area 45), via the insula, allows access to semantic networks in the dorsolateral prefrontal cortex so that the meaning and pronunciation of the words can be retrieved. Finally, either subvocal articulation or reading aloud is accompanied by activation of the whole of Broca’s area, the medial supplementary motor area (area 6), motor areas subserving face and tongue (area 4), and the contralateral cerebellar hemisphere.”
Neuroscience by Alan Longstaff
The Wernicke-Geschwind model
“Norman Geschwind assembled these clues into an explanation how we use language. When you read aloud, the words (1) register in the visual area, (2) are relayed to the angular gyrus that transforms the words into an auditory code that is (3) received and understood in the nearby Wernicke’s area and (4) sent to Broca’s area, which (5) controls the motor complex, creating the pronounced word. Damage to the angular gyrus leaves the person able to speak and understand but unable to read. Damage to Wernicke’s area disrupts understanding. (Comment: Reading, both aloud and for comprehension, is usually impaired in Wernicke's aphasia.) Damage to Broca’s area disrupts speaking (Comment: often also reading aloud).
The general principle bears repeating: complex abilities result from the intricate coordination of many brain areas. Said another way, the brain operates by dividing its mental functions – speaking, perceiving, thinking, remembering – into subfunctions. Our conscious experience seems indivisible. The brain computes the word’s form, sound, and meaning using different neural networks… To sum up, the mind’s subsystems are localized in particular brain regions, yet the brain acts as a unified whole.”
Psychology, Seventh Edition in Modules
by David G. Myers
A critique of the Wernicke-Geschwind model
“PET studies have revealed that because visual linguistic stimuli are not transformed into an auditory representation, visual and auditory linguistic stimuli are processed independently by modality-specific pathways that have independent access to Broca's area. Moreover, because the linguistic processing of visual stimuli can bypass Wernicke's area altogether, other brain regions must be involved with storing the meaning of words (Mayeux & Kandel, 1991,p. 845; also see Kolb & Whishaw, 1990, pp. 582-583). Thus, not only do there seem to be separate -- parallel -- pathways for processing the phonological and semantic aspects of language, language processing clearly involves a larger number of areas and a more complex set of interconnections than just those identified by the W-G model (Wernicke-Geschwind model) (Mayeux & Kandel, 1991, p. 845). Indeed, the PET studies support the notion that language production and comprehension involve processing along multiple routes, not just one:
No one area of the brain is devoted to a very complex function, such as 'syntax' or 'semantics'. Rather, any task or function utilizes a set of brain areas that form an interconnected, parallel, and distributed hierarchy. Each area within the hierarchy makes a specific contribution to the performance of the task. (Fiez & Petersen, 1993, 287)."
Using Pet Toward A Naturalized Model Of Human Language Processing
By Robert S. Stufflebeam
Active reading
“Recall that according to Wernicke both visual and auditory information are transformed into a shared auditory representation of language. This information is then conveyed to Wernicke’s area, where it becomes associated with meaning before being transformed in Broca’s area into output as written or spoken language…Using PET imaging, they determined how individual words are coded in the brain when the words are read or heard. They found that when words are heard, Wernicke’s area becomes active, but when words are seen but not heard or spoken, there is no activation of Wernicke’s area. The visual information from the occipital cortex appears to be conveyed directly to Broca’s area without first being transformed into an auditory representation in the posterior temporal cortex.”
Essentials of neural science and behavior by Eric R. Kandel, James Harris Schwartz, Thomas M. Jessell
Thursday, August 13, 2009
Evidence of Mirror Neurons in Human Inferior Frontal Gyrus
That's Broca's area. Mirror neurons may indeed play an important part in second language acquisition. Mirror neurons are supposed to be all about observation and imitation. Interhemispheric foreign language learning
"There is much current debate about the existence of mirror neurons in humans. To identify mirror neurons in the inferior frontal gyrus (IFG) of humans, we used a repetition suppression paradigm while measuring neural activity with functional magnetic resonance imaging. Subjects either executed or observed a series of actions. Here we show that in the IFG, responses were suppressed both when an executed action was followed by the same rather than a different observed action and when an observed action was followed by the same rather than a different executed action. This pattern of responses is consistent with that predicted by mirror neurons and is evidence of mirror neurons in the human IFG. 10.1523/JNEUROSCI.2668-09.2009"
link
First Evidence Found of Mirror Neuron’s Role in Language
"...the findings suggest that mirror neurons play a key role in the mental "re-enactment" of actions when linguistic descriptions of those actions are conceptually processed."
"There is much current debate about the existence of mirror neurons in humans. To identify mirror neurons in the inferior frontal gyrus (IFG) of humans, we used a repetition suppression paradigm while measuring neural activity with functional magnetic resonance imaging. Subjects either executed or observed a series of actions. Here we show that in the IFG, responses were suppressed both when an executed action was followed by the same rather than a different observed action and when an observed action was followed by the same rather than a different executed action. This pattern of responses is consistent with that predicted by mirror neurons and is evidence of mirror neurons in the human IFG. 10.1523/JNEUROSCI.2668-09.2009"
link
First Evidence Found of Mirror Neuron’s Role in Language
"...the findings suggest that mirror neurons play a key role in the mental "re-enactment" of actions when linguistic descriptions of those actions are conceptually processed."
Tuesday, August 11, 2009
Looking under the hood
Looking under the hood of language processing and language learning
The Broca’s area is a region of the brain responsible for speech articulation. It controls the motor complex which is responsible for speech production. “For a long time, it was assumed that the role of Broca's area was more devoted to language production than language comprehension. However, recent evidence demonstrates that Broca's area also plays a significant role in language comprehension. Patients with lesions in Broca's area who exhibit agrammatical speech production also show inability to use syntactic information to determine the meaning of sentences.[4] Also, a number of neuroimaging studies have implicated an involvement of Broca's area, particularly of the pars opercularis of the left inferior frontal gyrus, during the processing of complex sentences.(Wikipedia)
“More recently, Broca's area has been implicated in music processing, leading some researchers to suggest music may be processed as a language. Imaging studies have revealed that professional musicians trained at an early age have an increased volume of gray matter in Broca's area. Broca's area is part of a language and music processing network that includes Wernicke's area, the superior temporal sulcus, Heschl's gyrus, planum polare, planum temporale, and the anterior superior insular cortices.” Link
(Comment: Broca's area is essential for producing language and mediating grammar. The Broca’s area of the brain of Emil Krebs was larger and organized differently from that of monolingual men. It is unclear whether this was from birth or whether it was due to language learning).
Superior temporal gyrus: "a gyrus in the upper part of the temporal lobe. Contains the primary auditory cortex. The anterior part of this region has been implicated in generating the aha! experience of insight.” Link
Averbia is a specific type of anomia in which the subject has trouble remembering only verbs. This is caused by damage to the frontal cortex, in or near Broca's area.
Brain imaging findings:
Thinking about words makes the Broca’s area light up.
Thinking about words and speaking generates widespread activity.
Inner speech – Broca’s area active
Word retrieval (lexical information) – Broca’s involved
Prosody (musical intonation of speech) – Broca’s involved
Preparing to speak – Broca’s area active
The superior temporal gyrus contains several important structures of the brain, including: Brodmann areas 41 and 42, marking the location of the primary auditory cortex, the cortical region responsible for the sensation of sound; Wernicke's area, Brodmann 22p, an important region for the processing of speech so that it can be understood as language. (Wikipedia)
The auditory association area (Wernicke's area, or area 22) is an important region for the processing of acoustic signals so that they can be distinguished as speech, music, or noise. It is located within the temporal lobe of the brain, posterior to the primary auditory cortex. It is considered a part of the temporal cortex. It stores memories of sounds and permits perception of sounds. Wernicke's area (posterior part of the superior temporal gyrus) is connected to Broca's area via the arcuate fasciculus, a neural pathway, and to the visual cortex via the angular gyrus. It is the semantic processing center of the brain which plays a significant role in the conscious comprehension and interpretation of spoken words by both the listener and speaker. Words are not understood until they are processed by Wernicke’s area.
Primary auditory cortex. Located at the superior margin of the temporal lobe. Receives information related to pitch, rhythm and loudness.
Basal ganglia are large knots of nerve cells deep in the cerebrum. Structures contained in the basal ganglia include the amygdala, globus pallidus, and striatum (containing the caudate nucleus and the putamen). The basal ganglia (or basal nuclei) are interconnected with the cerebral cortex, thalamus and brainstem. They are associated with motor control and learning and participate in concert with the cortex in cognition and emotions. Parkinson's disease is an affliction of the basal ganglia. New (controversial) evidence suggests that these structures may also be involved in language processing.
“The Declarative/Procedural Model of Pinker, Ullman and colleagues claims that the basal ganglia are part of a fronto-striatal procedural memory system which applies grammatical rules to combine morphemes (the smallest meaningful units in language) into complex words (e.g. talk-ed, talk-ing). We tested this claim by investigating whether striatal damage or loss of its dopaminergic innervation is reliably associated with selective regular past tense deficits in patients with subcortical cerebrovascular damage, Parkinson’s disease or Huntington’s disease. We focused on past tense morphology since this allows us to contrast the regular past tense (jump-jumped), which is rule-based, with the irregular past tense (sleep-slept), which is not…. All patient groups showed normal activation of semantic and morphological representations in comprehension, despite difficulties suppressing semantically appropriate alternatives when trying to inflect novel verbs. This is consistent with previous reports that striatal dysfunction spares automatic activation of linguistic information, but disrupts later language processes that require inhibition of competing alternatives.
It seems more likely that neocortical regions are critical for this processing rather than the basal ganglia. Such a conclusion would be consistent with our recent finding that healthy volunteers show increased activation of the left inferior frontal gyrus and the left superior temporal gyrus when processing the regular past tense than irregular forms or words matched to past tense phonology (Marslen-Wilson et al., 2003)."
The basal ganglia and rule-governed language use: evidence from vascular and degenerative conditions by C. E. Longworth, S. E. Keenan, R. A. Barker, W. D. Marslen-Wilson and L. K. Tyler
(Comment: language processing is different from language learning).
“In the case of adult language learning, for example, proceduralized linguistic input may eventually be stored in the neocortex, but only after making a loop through the circuits of the basal ganglia… Immersion learning is slightly more procedural in nature, whereas classroom learning is slightly more declarative. Although in the past several decades, some teaching methods have endeavored to change this.”
The Neurobiology of Learning
By John H. Schumann, Sheila E. Crowell, Nancy E. Jones, Namhee Lee
The striatum is a subcortical part of the cerebrum. It is the major input station of the basal ganglia system and the part of the basal ganglia with the most complex shape.
"At a subcortical level, the main connections are located at the striatum. There is convincing evidence that highly automatized language skills are processed at this level. Agloti, Beltramello, Girardi, and Fabbro (1996) reported a case of aphasia where the patient had been bilingual in a Venetian dialect and standard Italian, two rather different languages. Her first and daily language was Venetian. However, after a stroke, she lost her Venetian language completely and was only able to speak standard Italian. It turned out that her brain damage was located at the subcortical level at striatum."
"Recent functional neuroimaging studies support a likely role for the dominant striatum in language, as activations were found during various different tasks such as speech, syntactic processing, lexical processing, word memorisation, word retrieval, and writing."
link
Comment: The brain learns in two different ways. One, called declarative learning, involves the medial temporal lobe and deals with learning active facts that can be recalled and used with great flexibility. Declarative learning and memory (also called explicit learning or, simply, memory) involves rapid learning, conscious recollection, and explicit declaration. It happens after language development. It is characterized by analytical, language-based, memory-dependent approach to acquiring and retaining knowledge. Distraction-free studying is more efficient and effective for this type of learning.
The second, involving the striatum, is called habit learning. There is convincing scientific evidence that highly automatized language skills are processed at this level.
The two types of learning compete with each other, and when someone is distracted habit learning takes over from declarative learning. One learns better particular habitual tasks while declarative learning suffers. The declarative and procedural memory systems interact both cooperatively and competitively in the acquisition and use of language.
And what is the outcome of successful language learning?
"Expert language learners attain a level of competence that is virtually comparable to that of native speakers (Coppieters 1987; Birdsong 1992,1997). The final state of these speakers is near-native – their “mental package” must look a lot like a native grammar since it includes phonological, morphological and syntactic rules. The documentation strongly suggests that these expert L2ers do indeed possess a grammar and not simply a collection of cognitive facts and strategies. Furthermore, while an intermediate L2 grammar appears to be less complete than the expert’s, it shares many of the characteristics of the superior L2er. Third, L2ers acquire knowledge that they are not taught and which does not transfer from the L1… This kind of evidence strongly supports the claim that knowledge of L2 is internally systematic, procedural and untaught; it is grammatical, not exclusively cognitive.
The documentation furnished by brain scans and neuro-electrical measurement complements and corroborates studies of language deprivation indicating a post-Critical Period loss of ability to acquire L1 morphosyntax (Curtiss 1988), but a persistent ability to acquire lexical items… It is evident that the neurological “etching” (Platzack 1996) of L1 must take place during the first five years of life for grammar to be really well established. If the L1 is so engraved, there is a grammar template for the L1 and for future additional languages. Child bilinguals have a double grammar in the Broca’s area of the brain, while adult bilinguals construct a second (L2) grammar separate from L1, BUT IN THE SAME APPROXIMATE REGION (Kim et al. 1997). Given the (often subtle) deficiencies of L2 grammars, one may infer that the L2 grammar is less deeply engraved. In contrast to grammatical knowledge, lexical information for both L1 and L2 is stored and accessed in a similar manner (Weber-Fox and Neville 1999)…. The L1 provides the template that permits the acquisition of L2, but ironically also interferes with that acquisition by the very depth of L1 neurological engraving…”
The second time around by Julia Rogers Herschensohn
An opposing view:
"Among the factors that typically lead to native-like proficiency in L2, aptitude, meaning the ability to learn explicitly, becomes one of the major variables. The fact that cognitive aptitude strongly correlates with success of L2 learning (Ehrman & Oxford, 1995) again suggests that high attainment in L2 is the result of learning rather than acquisition. All these factors are associated with learning performance in any knowledge domain subserved by declarative memory."
Declarative and Procedural Determinants of Second Languages by Michel Paradis
The Broca’s area is a region of the brain responsible for speech articulation. It controls the motor complex which is responsible for speech production. “For a long time, it was assumed that the role of Broca's area was more devoted to language production than language comprehension. However, recent evidence demonstrates that Broca's area also plays a significant role in language comprehension. Patients with lesions in Broca's area who exhibit agrammatical speech production also show inability to use syntactic information to determine the meaning of sentences.[4] Also, a number of neuroimaging studies have implicated an involvement of Broca's area, particularly of the pars opercularis of the left inferior frontal gyrus, during the processing of complex sentences.(Wikipedia)
“More recently, Broca's area has been implicated in music processing, leading some researchers to suggest music may be processed as a language. Imaging studies have revealed that professional musicians trained at an early age have an increased volume of gray matter in Broca's area. Broca's area is part of a language and music processing network that includes Wernicke's area, the superior temporal sulcus, Heschl's gyrus, planum polare, planum temporale, and the anterior superior insular cortices.” Link
(Comment: Broca's area is essential for producing language and mediating grammar. The Broca’s area of the brain of Emil Krebs was larger and organized differently from that of monolingual men. It is unclear whether this was from birth or whether it was due to language learning).
Superior temporal gyrus: "a gyrus in the upper part of the temporal lobe. Contains the primary auditory cortex. The anterior part of this region has been implicated in generating the aha! experience of insight.” Link
Averbia is a specific type of anomia in which the subject has trouble remembering only verbs. This is caused by damage to the frontal cortex, in or near Broca's area.
Brain imaging findings:
Thinking about words makes the Broca’s area light up.
Thinking about words and speaking generates widespread activity.
Inner speech – Broca’s area active
Word retrieval (lexical information) – Broca’s involved
Prosody (musical intonation of speech) – Broca’s involved
Preparing to speak – Broca’s area active
The superior temporal gyrus contains several important structures of the brain, including: Brodmann areas 41 and 42, marking the location of the primary auditory cortex, the cortical region responsible for the sensation of sound; Wernicke's area, Brodmann 22p, an important region for the processing of speech so that it can be understood as language. (Wikipedia)
The auditory association area (Wernicke's area, or area 22) is an important region for the processing of acoustic signals so that they can be distinguished as speech, music, or noise. It is located within the temporal lobe of the brain, posterior to the primary auditory cortex. It is considered a part of the temporal cortex. It stores memories of sounds and permits perception of sounds. Wernicke's area (posterior part of the superior temporal gyrus) is connected to Broca's area via the arcuate fasciculus, a neural pathway, and to the visual cortex via the angular gyrus. It is the semantic processing center of the brain which plays a significant role in the conscious comprehension and interpretation of spoken words by both the listener and speaker. Words are not understood until they are processed by Wernicke’s area.
Primary auditory cortex. Located at the superior margin of the temporal lobe. Receives information related to pitch, rhythm and loudness.
Basal ganglia are large knots of nerve cells deep in the cerebrum. Structures contained in the basal ganglia include the amygdala, globus pallidus, and striatum (containing the caudate nucleus and the putamen). The basal ganglia (or basal nuclei) are interconnected with the cerebral cortex, thalamus and brainstem. They are associated with motor control and learning and participate in concert with the cortex in cognition and emotions. Parkinson's disease is an affliction of the basal ganglia. New (controversial) evidence suggests that these structures may also be involved in language processing.
“The Declarative/Procedural Model of Pinker, Ullman and colleagues claims that the basal ganglia are part of a fronto-striatal procedural memory system which applies grammatical rules to combine morphemes (the smallest meaningful units in language) into complex words (e.g. talk-ed, talk-ing). We tested this claim by investigating whether striatal damage or loss of its dopaminergic innervation is reliably associated with selective regular past tense deficits in patients with subcortical cerebrovascular damage, Parkinson’s disease or Huntington’s disease. We focused on past tense morphology since this allows us to contrast the regular past tense (jump-jumped), which is rule-based, with the irregular past tense (sleep-slept), which is not…. All patient groups showed normal activation of semantic and morphological representations in comprehension, despite difficulties suppressing semantically appropriate alternatives when trying to inflect novel verbs. This is consistent with previous reports that striatal dysfunction spares automatic activation of linguistic information, but disrupts later language processes that require inhibition of competing alternatives.
It seems more likely that neocortical regions are critical for this processing rather than the basal ganglia. Such a conclusion would be consistent with our recent finding that healthy volunteers show increased activation of the left inferior frontal gyrus and the left superior temporal gyrus when processing the regular past tense than irregular forms or words matched to past tense phonology (Marslen-Wilson et al., 2003)."
The basal ganglia and rule-governed language use: evidence from vascular and degenerative conditions by C. E. Longworth, S. E. Keenan, R. A. Barker, W. D. Marslen-Wilson and L. K. Tyler
(Comment: language processing is different from language learning).
“In the case of adult language learning, for example, proceduralized linguistic input may eventually be stored in the neocortex, but only after making a loop through the circuits of the basal ganglia… Immersion learning is slightly more procedural in nature, whereas classroom learning is slightly more declarative. Although in the past several decades, some teaching methods have endeavored to change this.”
The Neurobiology of Learning
By John H. Schumann, Sheila E. Crowell, Nancy E. Jones, Namhee Lee
The striatum is a subcortical part of the cerebrum. It is the major input station of the basal ganglia system and the part of the basal ganglia with the most complex shape.
"At a subcortical level, the main connections are located at the striatum. There is convincing evidence that highly automatized language skills are processed at this level. Agloti, Beltramello, Girardi, and Fabbro (1996) reported a case of aphasia where the patient had been bilingual in a Venetian dialect and standard Italian, two rather different languages. Her first and daily language was Venetian. However, after a stroke, she lost her Venetian language completely and was only able to speak standard Italian. It turned out that her brain damage was located at the subcortical level at striatum."
"Recent functional neuroimaging studies support a likely role for the dominant striatum in language, as activations were found during various different tasks such as speech, syntactic processing, lexical processing, word memorisation, word retrieval, and writing."
link
Comment: The brain learns in two different ways. One, called declarative learning, involves the medial temporal lobe and deals with learning active facts that can be recalled and used with great flexibility. Declarative learning and memory (also called explicit learning or, simply, memory) involves rapid learning, conscious recollection, and explicit declaration. It happens after language development. It is characterized by analytical, language-based, memory-dependent approach to acquiring and retaining knowledge. Distraction-free studying is more efficient and effective for this type of learning.
The second, involving the striatum, is called habit learning. There is convincing scientific evidence that highly automatized language skills are processed at this level.
The two types of learning compete with each other, and when someone is distracted habit learning takes over from declarative learning. One learns better particular habitual tasks while declarative learning suffers. The declarative and procedural memory systems interact both cooperatively and competitively in the acquisition and use of language.
And what is the outcome of successful language learning?
"Expert language learners attain a level of competence that is virtually comparable to that of native speakers (Coppieters 1987; Birdsong 1992,1997). The final state of these speakers is near-native – their “mental package” must look a lot like a native grammar since it includes phonological, morphological and syntactic rules. The documentation strongly suggests that these expert L2ers do indeed possess a grammar and not simply a collection of cognitive facts and strategies. Furthermore, while an intermediate L2 grammar appears to be less complete than the expert’s, it shares many of the characteristics of the superior L2er. Third, L2ers acquire knowledge that they are not taught and which does not transfer from the L1… This kind of evidence strongly supports the claim that knowledge of L2 is internally systematic, procedural and untaught; it is grammatical, not exclusively cognitive.
The documentation furnished by brain scans and neuro-electrical measurement complements and corroborates studies of language deprivation indicating a post-Critical Period loss of ability to acquire L1 morphosyntax (Curtiss 1988), but a persistent ability to acquire lexical items… It is evident that the neurological “etching” (Platzack 1996) of L1 must take place during the first five years of life for grammar to be really well established. If the L1 is so engraved, there is a grammar template for the L1 and for future additional languages. Child bilinguals have a double grammar in the Broca’s area of the brain, while adult bilinguals construct a second (L2) grammar separate from L1, BUT IN THE SAME APPROXIMATE REGION (Kim et al. 1997). Given the (often subtle) deficiencies of L2 grammars, one may infer that the L2 grammar is less deeply engraved. In contrast to grammatical knowledge, lexical information for both L1 and L2 is stored and accessed in a similar manner (Weber-Fox and Neville 1999)…. The L1 provides the template that permits the acquisition of L2, but ironically also interferes with that acquisition by the very depth of L1 neurological engraving…”
The second time around by Julia Rogers Herschensohn
An opposing view:
"Among the factors that typically lead to native-like proficiency in L2, aptitude, meaning the ability to learn explicitly, becomes one of the major variables. The fact that cognitive aptitude strongly correlates with success of L2 learning (Ehrman & Oxford, 1995) again suggests that high attainment in L2 is the result of learning rather than acquisition. All these factors are associated with learning performance in any knowledge domain subserved by declarative memory."
Declarative and Procedural Determinants of Second Languages by Michel Paradis
Saturday, August 8, 2009
Fossilization, automatization and second language acquisition research
Excerpts from “The Neurobiology of Learning”
by John H. Schumann, Sheila E. Crowell, Nancy E. Jones, Namhee Lee
“Aphasic syndromes caused by BG (basal ganglia) lesions indicate what roles the BG may play in language functions. According to Fabbro (1999), basal ganglia aphasics develop symptoms such as reduced voice volume, foreign accent syndrome, perseveration (involuntary repetition of words, syllables etc.), and agrammatism. Additionally a polyglot’s more fluent language tends to be more seriously damaged than a less fluent language. The interesting fact that the patients’ second languages are better preserved may imply that their second languages are processed more by the declarative memory system. Although the automatization of a second language through the BD is ongoing, it may not be complete. When a patient suffers a BG lesion, the parts of the second language that have already been proceduralized wil be damaged, but other parts of SL that have not been proceduralized will be preserved. In contrast, a first language may have been almost completely proceduralized without leaving much of a trace in the declarative system. This may be why BG-lesion patients cannot produce their first language in spite of their intact declarative memory system...
Knowledge about the BG functions may have important implications for the area of linguistics in general and SLA in particular.
Learning fixed expressions: Chunking
Some researchers have noticed that second language learners tend to learn frequently co-occurring words and delexicalized chunks (Sinclair 1991; Tannen, 1989). This phenomenon may be explained by the chunking mechanism of the BG. Previously, we discussed how the BG participates in the process of chunking the cortically distributed information into a unitary sequence through convergence, divergence and reconvergence. Whenever a second language speaker uses one of the fixed expression, he or she may simply activate the relevant basal ganglia circuit so that he or she does not need to apply a grammar rule or a phonological rule step by step.
Automatization of Syntax and Phonology: DP and IP
Learning and producing the phonology and grammar of a target language probably involve both the direct pathway and the indirect pathway. Through numerous repetitive inputs of the target language and its production, a second language speaker may slowly build up stronger synapses among participating neurons in the cortex and basal ganglia, which represent the syntactic and phonological rules of the target language. Finaly the learner acquires the ability to execute the rules through the direct pathway of the BG. For example, the choice of word order may be the result of basal ganglia function.
Whenever a second language speaker utters a sentence, perhaps there may be two competing word orders in the speaker’s brain, one probably from his or her first language and another from the target language. When the speaker gets into the target language mode,the target language order may be executed through the direct pathway with the competing order being inhibited by the indirect pathway. Other aspects of grammar may be the same.
Phonology is likely to develop in the same way… As the learner improves his or her fluency in the target language through numerous repetitions in listening and speaking, he or she may acquire the ability to execute this rule through the direct pathway.
(Comment: Pronunciation does improve with language use, regardless of the initial silent period. Even after a long silent period the learner's pronunciation will suffer while he struggles to build sentences. However, unlike the early bird, he will always be able to rely on his good ear for the language. If one insists on speaking from the very start and without paying attention to phonology, automatization results in a lot of fossilized errors and fossilization is unfortunately the strongest and most difficult to eradicate at the phonological level. I’ll leave the silent period hypothesis aside. One also needs to consider the usefulness to effort ratio and the “permanent damage” theory.)
Formation of Rules of the Target Language
The formation of correct rules is often a difficult process. To form a correct rule, a speaker has to frequently execute the correct sentences related to the rule. However, a beginner cannot execute the correct sentence easily, and every time he or she executes an incorrect sentence, the wrong rule will be strengthened in the relevant neuronal circuits. A paradoxical situation is unavoidable here. The more often a beginner utters incorrect sentences, the stronger the neuronal circuits representing them may become. However, advanced second language speakers conform to the rules of the target language to a greater extent than beginners.”
(Comment: certainly a lot of wasted synapses)
“Fossilized language speakers have two important characteristics (Harley and Swain, 1978; Selinker, 1972). One is that they have already acquired a certain level of communicative fluidity. They can generate utterances in the target language without undue cognitive planning and without consciously building structures. They show less hesitation when engaged in conversation. In summary their speech has fluency. Another characteristic of fossilized second language speakers is that their learning has stopped or radically slowed down. Their typical utterance structures and phonology do not improve over time although they may be continuously exposed to the target language environment. They continue to make the same grammatical and phonological errors although they are sometimes aware that they are doing so.
(Comment: In second language acquisition the mighty brain is not always your friend. Message transmitted, message received - the path of least resistance. The native error correction mechanism also contributes negatively since the learner is not encouraged to reformulate his utterance. A possible workaround: a decent silent period, careful production).
“These two characteristics may be explained by BG functions and procedural memory. The first characteristic of fossilized second language speakers, natural fluidity, occurs because they have already acquired the target language procedurally, thus, they have obtained automaticity. By repetitive use of the target language, the speakers may have formed procedural memory of (incorrect) linguistic rules of the target language through the basal ganglia circuits. When one acquires a procedural memory of a motor or a cognitive skill, one can execute it automatically…
The other characteristic of the speakers, rigidity of errors, can also be explained with reference to the BG and procedural memory… Procedural memory is formed more slowly than declarative memory. The other side of the coin is that procedural memory is more robust so that, once formed, it is better preserved, and it is also inflexible, and therefore difficult to change. This is why it is so difficult to correct bad habits… If a fossilized second language speaker has already automatized the linguistic skills through basal ganglia circuits, the automatized skils are naturally resistant to correction and change.
An outstanding question is whether fossilized language can be defossilized… First, defossilization perhaps is possible. It is not too rare to meet fossilized speakers in a language classroom. (No kidding!).
This may be possible for two neurobiological reasons. First the brain is always plastic, although the extent of plasticity varies according to many factors. Because the brain maintains plasticity, it is not impossible to form a new rule or to correct an incorrect rule. Second, the anatomy of the brain shows that the procedural memory of the basal ganglia can be influenced by other components…. Dopamine (DA), which is involved motivational modulation of its targets, is very important in this system, projecting from the ventral…to the ventral striatum, the ventral pallidum and the dorsal striatum.
From experience, we all know that automatizing declarative knowledge or altering a habitual procedure is difficult and time-consuming. It requires practice and motivation to sustain that practice. Animals probably acquire declarative and procedural knowledge together as they experience the world. With humans, the symbolic species capable of language, it becomes possible to acquire declarative and procedural skills more separately. This type of learning requires cognitive work and the motivation to do that work. The task, of course, is facilitated by aptitude. From an evolutionary perspective, it is easy to understand why it may be difficult to alter motor procedures. Procedures are developed to help the organism thrive in the environment by allowing automatic responses to stimuli. If they were easily altered or disrupted, the animal’s survival would be threatened. Therefore, when a language learner develops incorrect grammatical structure, these habit-protecting difficulties are encountered, and considerable effort is required to develop the correct procedures to override the maladaptive fossilization”.
Krashen from neurobiological perspective
“Though Krashen himself did not attempt to make a biology-based argument, there are several possible biological assumptions inherent in his position. These are:
1 The areas of the brain involved in subconscious processes (acquisition) are different from those areas involved in conscious processes (learning). That is to say, declarative and nondecalrative learning are accomplished by different areas of the brain.
2 There are no connections between these two brain regions.
3. The declarative system cannot modulate activity in the nondeclarative system. In other words, practicing an explicitly learned rule over and over again will not help the learner to strengthen connections in areas of the brain responsible for proceduralization.
Currently, SLA theorists are moving away from Krashen’s noninterface position, and are taking the stance that rule acquisition in language is a complex cognitive task that lies on the same power function learning curve as other cognitive skills (DeKeyser, 1997). These researchers suggest that SLA is similar to the acquisition of most skills, which appear to involve interactions between the declarative and the nondeclarative memory systems (Berry, 1994, Ellis, 2000;MacWhinney, 1997). Elis, for example, discussed three likely ways in which implicit and explicit knowledge might be converted into implicit knowledge if the learner is at the right stage of linguistic development. Second, explicit knowledge may lead the learner to listen for a recently learned language structure in the input. Third, explicit knowledge might cause learners to notice differences between their own output and the output of native seakers (Ellis, 2000). These three points are not only borne out by observations of adult language learners, they are also true of the underlying biology. Perhaps only the first of the three points needs some revision based on the research presented in this book. Specifically, we would assert that knowledge that is stored declaratively is not converted into nondeclarative knowledge. Instead, learners acquire and store information in both declarative (hippocampus/cortex) loops and nondeclarative (basal ganglia/cortex) loops…
MacWhinney (1997) “cited a number of sources claiming that second language learning is facilitated by explicit instruction. However, he also suggested that implicit learing may still play an important rule in the acquisition of a second language. Further, MacWhinney suggested that explicit instruction may actually be harmful if the structures that are being taught are too complicated, irregular, or simplified to the point of being incorrect…
It is likely that there are significant individual differences in the number of cycles through the hippocampus that are needed for each student to learn a rule, as well as differences in the number of cycles required for different rules for the same student. While some students may immediately recognize the discrepancy between the two forms and rapidly begin producing target-like utterances, other students ay take weeks or even months to resolve this conflict. One reason for this difference is that each student’s brai has been shaped by idiosyncratice experiences. Furthermore, as was previously discussed, this difference between students may partially result from individual differences in the genes responsible for activating the transcription factors CREB and C/EBP.”
by John H. Schumann, Sheila E. Crowell, Nancy E. Jones, Namhee Lee
“Aphasic syndromes caused by BG (basal ganglia) lesions indicate what roles the BG may play in language functions. According to Fabbro (1999), basal ganglia aphasics develop symptoms such as reduced voice volume, foreign accent syndrome, perseveration (involuntary repetition of words, syllables etc.), and agrammatism. Additionally a polyglot’s more fluent language tends to be more seriously damaged than a less fluent language. The interesting fact that the patients’ second languages are better preserved may imply that their second languages are processed more by the declarative memory system. Although the automatization of a second language through the BD is ongoing, it may not be complete. When a patient suffers a BG lesion, the parts of the second language that have already been proceduralized wil be damaged, but other parts of SL that have not been proceduralized will be preserved. In contrast, a first language may have been almost completely proceduralized without leaving much of a trace in the declarative system. This may be why BG-lesion patients cannot produce their first language in spite of their intact declarative memory system...
Knowledge about the BG functions may have important implications for the area of linguistics in general and SLA in particular.
Learning fixed expressions: Chunking
Some researchers have noticed that second language learners tend to learn frequently co-occurring words and delexicalized chunks (Sinclair 1991; Tannen, 1989). This phenomenon may be explained by the chunking mechanism of the BG. Previously, we discussed how the BG participates in the process of chunking the cortically distributed information into a unitary sequence through convergence, divergence and reconvergence. Whenever a second language speaker uses one of the fixed expression, he or she may simply activate the relevant basal ganglia circuit so that he or she does not need to apply a grammar rule or a phonological rule step by step.
Automatization of Syntax and Phonology: DP and IP
Learning and producing the phonology and grammar of a target language probably involve both the direct pathway and the indirect pathway. Through numerous repetitive inputs of the target language and its production, a second language speaker may slowly build up stronger synapses among participating neurons in the cortex and basal ganglia, which represent the syntactic and phonological rules of the target language. Finaly the learner acquires the ability to execute the rules through the direct pathway of the BG. For example, the choice of word order may be the result of basal ganglia function.
Whenever a second language speaker utters a sentence, perhaps there may be two competing word orders in the speaker’s brain, one probably from his or her first language and another from the target language. When the speaker gets into the target language mode,the target language order may be executed through the direct pathway with the competing order being inhibited by the indirect pathway. Other aspects of grammar may be the same.
Phonology is likely to develop in the same way… As the learner improves his or her fluency in the target language through numerous repetitions in listening and speaking, he or she may acquire the ability to execute this rule through the direct pathway.
(Comment: Pronunciation does improve with language use, regardless of the initial silent period. Even after a long silent period the learner's pronunciation will suffer while he struggles to build sentences. However, unlike the early bird, he will always be able to rely on his good ear for the language. If one insists on speaking from the very start and without paying attention to phonology, automatization results in a lot of fossilized errors and fossilization is unfortunately the strongest and most difficult to eradicate at the phonological level. I’ll leave the silent period hypothesis aside. One also needs to consider the usefulness to effort ratio and the “permanent damage” theory.)
Formation of Rules of the Target Language
The formation of correct rules is often a difficult process. To form a correct rule, a speaker has to frequently execute the correct sentences related to the rule. However, a beginner cannot execute the correct sentence easily, and every time he or she executes an incorrect sentence, the wrong rule will be strengthened in the relevant neuronal circuits. A paradoxical situation is unavoidable here. The more often a beginner utters incorrect sentences, the stronger the neuronal circuits representing them may become. However, advanced second language speakers conform to the rules of the target language to a greater extent than beginners.”
(Comment: certainly a lot of wasted synapses)
“Fossilized language speakers have two important characteristics (Harley and Swain, 1978; Selinker, 1972). One is that they have already acquired a certain level of communicative fluidity. They can generate utterances in the target language without undue cognitive planning and without consciously building structures. They show less hesitation when engaged in conversation. In summary their speech has fluency. Another characteristic of fossilized second language speakers is that their learning has stopped or radically slowed down. Their typical utterance structures and phonology do not improve over time although they may be continuously exposed to the target language environment. They continue to make the same grammatical and phonological errors although they are sometimes aware that they are doing so.
(Comment: In second language acquisition the mighty brain is not always your friend. Message transmitted, message received - the path of least resistance. The native error correction mechanism also contributes negatively since the learner is not encouraged to reformulate his utterance. A possible workaround: a decent silent period, careful production).
“These two characteristics may be explained by BG functions and procedural memory. The first characteristic of fossilized second language speakers, natural fluidity, occurs because they have already acquired the target language procedurally, thus, they have obtained automaticity. By repetitive use of the target language, the speakers may have formed procedural memory of (incorrect) linguistic rules of the target language through the basal ganglia circuits. When one acquires a procedural memory of a motor or a cognitive skill, one can execute it automatically…
The other characteristic of the speakers, rigidity of errors, can also be explained with reference to the BG and procedural memory… Procedural memory is formed more slowly than declarative memory. The other side of the coin is that procedural memory is more robust so that, once formed, it is better preserved, and it is also inflexible, and therefore difficult to change. This is why it is so difficult to correct bad habits… If a fossilized second language speaker has already automatized the linguistic skills through basal ganglia circuits, the automatized skils are naturally resistant to correction and change.
An outstanding question is whether fossilized language can be defossilized… First, defossilization perhaps is possible. It is not too rare to meet fossilized speakers in a language classroom. (No kidding!).
This may be possible for two neurobiological reasons. First the brain is always plastic, although the extent of plasticity varies according to many factors. Because the brain maintains plasticity, it is not impossible to form a new rule or to correct an incorrect rule. Second, the anatomy of the brain shows that the procedural memory of the basal ganglia can be influenced by other components…. Dopamine (DA), which is involved motivational modulation of its targets, is very important in this system, projecting from the ventral…to the ventral striatum, the ventral pallidum and the dorsal striatum.
From experience, we all know that automatizing declarative knowledge or altering a habitual procedure is difficult and time-consuming. It requires practice and motivation to sustain that practice. Animals probably acquire declarative and procedural knowledge together as they experience the world. With humans, the symbolic species capable of language, it becomes possible to acquire declarative and procedural skills more separately. This type of learning requires cognitive work and the motivation to do that work. The task, of course, is facilitated by aptitude. From an evolutionary perspective, it is easy to understand why it may be difficult to alter motor procedures. Procedures are developed to help the organism thrive in the environment by allowing automatic responses to stimuli. If they were easily altered or disrupted, the animal’s survival would be threatened. Therefore, when a language learner develops incorrect grammatical structure, these habit-protecting difficulties are encountered, and considerable effort is required to develop the correct procedures to override the maladaptive fossilization”.
Krashen from neurobiological perspective
“Though Krashen himself did not attempt to make a biology-based argument, there are several possible biological assumptions inherent in his position. These are:
1 The areas of the brain involved in subconscious processes (acquisition) are different from those areas involved in conscious processes (learning). That is to say, declarative and nondecalrative learning are accomplished by different areas of the brain.
2 There are no connections between these two brain regions.
3. The declarative system cannot modulate activity in the nondeclarative system. In other words, practicing an explicitly learned rule over and over again will not help the learner to strengthen connections in areas of the brain responsible for proceduralization.
Currently, SLA theorists are moving away from Krashen’s noninterface position, and are taking the stance that rule acquisition in language is a complex cognitive task that lies on the same power function learning curve as other cognitive skills (DeKeyser, 1997). These researchers suggest that SLA is similar to the acquisition of most skills, which appear to involve interactions between the declarative and the nondeclarative memory systems (Berry, 1994, Ellis, 2000;MacWhinney, 1997). Elis, for example, discussed three likely ways in which implicit and explicit knowledge might be converted into implicit knowledge if the learner is at the right stage of linguistic development. Second, explicit knowledge may lead the learner to listen for a recently learned language structure in the input. Third, explicit knowledge might cause learners to notice differences between their own output and the output of native seakers (Ellis, 2000). These three points are not only borne out by observations of adult language learners, they are also true of the underlying biology. Perhaps only the first of the three points needs some revision based on the research presented in this book. Specifically, we would assert that knowledge that is stored declaratively is not converted into nondeclarative knowledge. Instead, learners acquire and store information in both declarative (hippocampus/cortex) loops and nondeclarative (basal ganglia/cortex) loops…
MacWhinney (1997) “cited a number of sources claiming that second language learning is facilitated by explicit instruction. However, he also suggested that implicit learing may still play an important rule in the acquisition of a second language. Further, MacWhinney suggested that explicit instruction may actually be harmful if the structures that are being taught are too complicated, irregular, or simplified to the point of being incorrect…
It is likely that there are significant individual differences in the number of cycles through the hippocampus that are needed for each student to learn a rule, as well as differences in the number of cycles required for different rules for the same student. While some students may immediately recognize the discrepancy between the two forms and rapidly begin producing target-like utterances, other students ay take weeks or even months to resolve this conflict. One reason for this difference is that each student’s brai has been shaped by idiosyncratice experiences. Furthermore, as was previously discussed, this difference between students may partially result from individual differences in the genes responsible for activating the transcription factors CREB and C/EBP.”
Ventral and dorsal pathways for language
The Two-Streams hypothesis
Introduction
The Two-Streams hypothesis is a widely accepted, but still controversial, account of visual processing. As visual information exits the occipital lobe, it follows two main channels, or "streams."
The ventral stream (also known as the "what pathway") is associated with object recognition and form representation. It has strong connections to the medial temporal lobe (which stores long-term memories), the limbic system (which controls emotions), and the dorsal stream (which deals with object locations and motion).
The dorsal stream (or, "where pathway") is involved in spatial awareness and guidance of actions (e.g., reaching). In this it has two distinct functional characteristics -it contains a detailed map of the visual field, and is also good at detecting and analyzing movements. The dorsal stream commences with purely visual functions in the occipital lobe before gradually transferring to spatial awareness at its termination in the parietal lobe. The posterior parietal cortex is essential for, "the perception and interpretation of spatial relationships, accurate body image, and the learning of tasks involving coordination of the body in space".
The dual stream model for language processing (a hot new hypothesis)
Abstract
Built on an analogy between the visual and auditory systems, the following dual stream model for language processing was suggested recently: a dorsal stream is involved in mapping sound to articulation, and a ventral stream in mapping sound to meaning. The goal of the study presented here was to test the neuroanatomical basis of this model. Combining functional magnetic resonance imaging (fMRI) with a novel diffusion tensor imaging (DTI)-based tractography method we were able to identify the most probable anatomical pathways connecting brain regions activated during two prototypical language tasks. Sublexical repetition of speech is subserved by a dorsal pathway, connecting the superior temporal lobe and premotor cortices in the frontal lobe via the arcuate and superior longitudinal fascicle. In contrast, higher-level language comprehension is mediated by a ventral pathway connecting the middle temporal lobe and the ventrolateral prefrontal cortex via the extreme capsule. Thus, according to our findings, the function of the dorsal route, traditionally considered to be the major language pathway, is mainly restricted to sensory-motor mapping of sound to articulation, whereas linguistic processing of sound to meaning requires temporofrontal interaction transmitted via the ventral route.
link
Dorsal and ventral streams: a framework for understanding aspects of the functional anatomy of language
Résumé / Abstract
Despite intensive work on language-brain relations, and a fairly impressive accumulation of knowledge over the last several decades, there has been little progress in developing large-scale models of the functional anatomy of language that integrate neuropsychological, neuroimaging, and psycholinguistic data. Drawing on relatively recent developments in the cortical organization of vision, and on data from a variety of sources, we propose a new framework for understanding aspects of the functional anatomy of language which moves towards remedying this situation. The framework posits that early cortical stages of speech perception involve auditory fields in the superior temporal gyrus bilaterally (although asymmetrically). This cortical processing system then diverges into two broad processing streams, a ventral stream, which is involved in mapping sound onto meaning, and a dorsal stream, which is involved in mapping sound onto articulatory-based representations. The ventral stream projects ventro-laterally toward inferior posterior temporal cortex (posterior middle temporal gyrus) which serves as an interface between sound-based representations of speech in the superior temporal gyrus (again bilaterally) and widely distributed conceptual representations. The dorsal stream projects dorso-posteriorly involving a region in the posterior Sylvian fissure at the parietal-temporal boundary (area Spt), and ultimately projecting to frontal regions. This network provides a mechanism for the development and maintenance of parity between auditory and motor representations of speech. Although the proposed dorsal stream represents a very tight connection between processes involved in speech perception and speech production, it does not appear to be a critical component of the speech perception process under normal (ecologically natural) listening conditions, that is, when speech input is mapped onto a conceptual representation. We also propose some degree of bi-directionality in both the dorsal and ventral pathways. We discuss some recent empirical tests of this framework that utilize a range of methods. We also show how damage to different components of this framework can account for the major symptom clusters of the fluent aphasias, and discuss some recent evidence concerning how sentence-level processing might be integrated into the framework.
link
Seems to support Wernicke's 1874 language model
"...Wernicke proposed that sensory representations of speech ("auditory word images") interfaced with two distinct systems, the conceptual system, which he believed was broadly distributed throughout cortex, and the motor system located in the frontal lobe. The interface with the conceptual system supported comprehension of speech, whereas the interface with the motor system helped support the production of speech. Thus, one stream processes the meaning of sensory information (the "what" stream), while the other allows for interaction with the action system (the "how" stream). This is basically identical to what David and I have been claiming in terms of broad organization of our dual stream model..."
Talking Brains
"Experimental data suggest that the division between the visual ventral and dorsal pathways may indeed indicate that static and dynamical information is processed separately. Contrary to Hurford, it is suggested that the ventral pathway primarily generates representations of objects, whereas the dorsal pathway produces representations of events. The semantic object/event distinction may relate to the morpho-syntactic noun/verb distinction."
Markus Werning (2003). Ventral Versus Dorsal Pathway: The Source of the Semantic Object/Event and the Syntactic Noun/Verb Distinction? Behavioral and Brain Sciences 26 (3):299-300.
Introduction
The Two-Streams hypothesis is a widely accepted, but still controversial, account of visual processing. As visual information exits the occipital lobe, it follows two main channels, or "streams."
The ventral stream (also known as the "what pathway") is associated with object recognition and form representation. It has strong connections to the medial temporal lobe (which stores long-term memories), the limbic system (which controls emotions), and the dorsal stream (which deals with object locations and motion).
The dorsal stream (or, "where pathway") is involved in spatial awareness and guidance of actions (e.g., reaching). In this it has two distinct functional characteristics -it contains a detailed map of the visual field, and is also good at detecting and analyzing movements. The dorsal stream commences with purely visual functions in the occipital lobe before gradually transferring to spatial awareness at its termination in the parietal lobe. The posterior parietal cortex is essential for, "the perception and interpretation of spatial relationships, accurate body image, and the learning of tasks involving coordination of the body in space".
The dual stream model for language processing (a hot new hypothesis)
Abstract
Built on an analogy between the visual and auditory systems, the following dual stream model for language processing was suggested recently: a dorsal stream is involved in mapping sound to articulation, and a ventral stream in mapping sound to meaning. The goal of the study presented here was to test the neuroanatomical basis of this model. Combining functional magnetic resonance imaging (fMRI) with a novel diffusion tensor imaging (DTI)-based tractography method we were able to identify the most probable anatomical pathways connecting brain regions activated during two prototypical language tasks. Sublexical repetition of speech is subserved by a dorsal pathway, connecting the superior temporal lobe and premotor cortices in the frontal lobe via the arcuate and superior longitudinal fascicle. In contrast, higher-level language comprehension is mediated by a ventral pathway connecting the middle temporal lobe and the ventrolateral prefrontal cortex via the extreme capsule. Thus, according to our findings, the function of the dorsal route, traditionally considered to be the major language pathway, is mainly restricted to sensory-motor mapping of sound to articulation, whereas linguistic processing of sound to meaning requires temporofrontal interaction transmitted via the ventral route.
link
Dorsal and ventral streams: a framework for understanding aspects of the functional anatomy of language
Résumé / Abstract
Despite intensive work on language-brain relations, and a fairly impressive accumulation of knowledge over the last several decades, there has been little progress in developing large-scale models of the functional anatomy of language that integrate neuropsychological, neuroimaging, and psycholinguistic data. Drawing on relatively recent developments in the cortical organization of vision, and on data from a variety of sources, we propose a new framework for understanding aspects of the functional anatomy of language which moves towards remedying this situation. The framework posits that early cortical stages of speech perception involve auditory fields in the superior temporal gyrus bilaterally (although asymmetrically). This cortical processing system then diverges into two broad processing streams, a ventral stream, which is involved in mapping sound onto meaning, and a dorsal stream, which is involved in mapping sound onto articulatory-based representations. The ventral stream projects ventro-laterally toward inferior posterior temporal cortex (posterior middle temporal gyrus) which serves as an interface between sound-based representations of speech in the superior temporal gyrus (again bilaterally) and widely distributed conceptual representations. The dorsal stream projects dorso-posteriorly involving a region in the posterior Sylvian fissure at the parietal-temporal boundary (area Spt), and ultimately projecting to frontal regions. This network provides a mechanism for the development and maintenance of parity between auditory and motor representations of speech. Although the proposed dorsal stream represents a very tight connection between processes involved in speech perception and speech production, it does not appear to be a critical component of the speech perception process under normal (ecologically natural) listening conditions, that is, when speech input is mapped onto a conceptual representation. We also propose some degree of bi-directionality in both the dorsal and ventral pathways. We discuss some recent empirical tests of this framework that utilize a range of methods. We also show how damage to different components of this framework can account for the major symptom clusters of the fluent aphasias, and discuss some recent evidence concerning how sentence-level processing might be integrated into the framework.
link
Seems to support Wernicke's 1874 language model
"...Wernicke proposed that sensory representations of speech ("auditory word images") interfaced with two distinct systems, the conceptual system, which he believed was broadly distributed throughout cortex, and the motor system located in the frontal lobe. The interface with the conceptual system supported comprehension of speech, whereas the interface with the motor system helped support the production of speech. Thus, one stream processes the meaning of sensory information (the "what" stream), while the other allows for interaction with the action system (the "how" stream). This is basically identical to what David and I have been claiming in terms of broad organization of our dual stream model..."
Talking Brains
"Experimental data suggest that the division between the visual ventral and dorsal pathways may indeed indicate that static and dynamical information is processed separately. Contrary to Hurford, it is suggested that the ventral pathway primarily generates representations of objects, whereas the dorsal pathway produces representations of events. The semantic object/event distinction may relate to the morpho-syntactic noun/verb distinction."
Markus Werning (2003). Ventral Versus Dorsal Pathway: The Source of the Semantic Object/Event and the Syntactic Noun/Verb Distinction? Behavioral and Brain Sciences 26 (3):299-300.
Thursday, August 6, 2009
Newborn Brain May Be Wired for Speech
Newborn Brain May Be Wired for Speech
By Faith Hickman Brynie
About Faith Hickman Brynie
July 07, 2008
The long, enthusiastic debate about whether the brain is hardwired for language gets a boost now and then, most recently from the release several months ago of a book claiming we are hardwired to, among other things, curse. Continuing research suggests that even though newborns cannot speak or understand language, our brains may indeed be built for language from birth or even before.
“From the first weeks of life the human brain is particularly adapted for processing speech,” says French researcher Ghislaine Dehaene-Lambertz, director of the cognitive neuroimaging research center at the Institut National de la Santé de la Recherche Médicale. Infants’ language learning and processing rely largely on the same brain circuits that adults use, she says.
Studies employing optical topography, a technique that assesses oxygen use in the brain, have shown activity in left-hemisphere speech centers in newborns as young as 2 to 5 days. Marcela Peña of the International School for Advanced Studies in Italy and colleagues found that left-hemisphere activity was greater when the babies hear normal speech than when they heard silence or speech played backward, according to a study published in the Proceedings of the National Academy of Sciences in 2003.
Other behavioral experiments have demonstrated that days- or weeks-old infants can distinguish the “melody” of their native language from the pitches and rhythms of other languages, and that infants can assess the number of syllables in a word and detect a change in speech sounds (such as ba versus ga), even when they hear different speakers.
In 2002 Dehaene-Lambertz’s team used functional magnetic resonance imaging (fMRI) to monitor brain activity while 3-month-old infants listened to 20-second blocks of speech played forward and backward. With forward speech, the same brain regions that adults use for language were active in the babies, with a strong preference for the left hemisphere.
Additional activation in parts of the right frontal cortex was seen in infants who listened to normal speech. The activity occurred in the same brain areas that become active when adults retrieve verbal information from memory.
The French team also found a significant preference for the native language in the babies’ left angular gyrus, an area with increased activity when adults hear words but not nonsense syllables.
In 2006 Dehaene-Lambertz again used fMRI to measure cerebral activity in 3-month-olds who heard short sentences spoken in their native language.
The infants recognized a repeated sentence even after a 14-second interval of silence. The scans showed adultlike activity in the upper region of the brain’s left temporal lobe. The fastest responses were recorded near the auditory cortex, where sounds are first processed in the brain.
Responses slowed down toward the back of the language-processing region and in Broca’s area in the left hemisphere. Activity in that area increased when a sentence was repeated, suggesting that infants may be using a memory system based on Broca’s area just as adults do. These results, reported in the Proceedings of the National Academy of Sciences, demonstrate that the precursors of adult cortical language areas are already working in infants even before the time when babbling begins, Dehaene-Lambertz says.
She offers two possible explanations for these findings. Perhaps certain brain regions are genetically and developmentally “programmed” for language at birth, or even before. Or perhaps these regions are sensitive only to sound or to any rapidly changing sound.
“We do not know yet whether another structured stimulus, such as music, would activate the same network,” Dehaene-Lambertz says. “However, we can say that the processing abilities of an infant’s brain make it efficiently adapted to the most frequent auditory input: speech.”
Edith Kaan, a linguist at the University of Florida, says that researchers are currently studying whether the developing brain handles speech sounds in a different way from other sounds. They also hope to discover how brain regions specialize as children learn to make and understand words, phrases and sentences.
“Eventually, this research may help us understand what capacities are inborn for learning language,” Kaan says. “We may also learn which functions are unique to language and language development, and which are shared with other cognitive activities such as attention, working memory and pattern recognition.”
link
By Faith Hickman Brynie
About Faith Hickman Brynie
July 07, 2008
The long, enthusiastic debate about whether the brain is hardwired for language gets a boost now and then, most recently from the release several months ago of a book claiming we are hardwired to, among other things, curse. Continuing research suggests that even though newborns cannot speak or understand language, our brains may indeed be built for language from birth or even before.
“From the first weeks of life the human brain is particularly adapted for processing speech,” says French researcher Ghislaine Dehaene-Lambertz, director of the cognitive neuroimaging research center at the Institut National de la Santé de la Recherche Médicale. Infants’ language learning and processing rely largely on the same brain circuits that adults use, she says.
Studies employing optical topography, a technique that assesses oxygen use in the brain, have shown activity in left-hemisphere speech centers in newborns as young as 2 to 5 days. Marcela Peña of the International School for Advanced Studies in Italy and colleagues found that left-hemisphere activity was greater when the babies hear normal speech than when they heard silence or speech played backward, according to a study published in the Proceedings of the National Academy of Sciences in 2003.
Other behavioral experiments have demonstrated that days- or weeks-old infants can distinguish the “melody” of their native language from the pitches and rhythms of other languages, and that infants can assess the number of syllables in a word and detect a change in speech sounds (such as ba versus ga), even when they hear different speakers.
In 2002 Dehaene-Lambertz’s team used functional magnetic resonance imaging (fMRI) to monitor brain activity while 3-month-old infants listened to 20-second blocks of speech played forward and backward. With forward speech, the same brain regions that adults use for language were active in the babies, with a strong preference for the left hemisphere.
Additional activation in parts of the right frontal cortex was seen in infants who listened to normal speech. The activity occurred in the same brain areas that become active when adults retrieve verbal information from memory.
The French team also found a significant preference for the native language in the babies’ left angular gyrus, an area with increased activity when adults hear words but not nonsense syllables.
In 2006 Dehaene-Lambertz again used fMRI to measure cerebral activity in 3-month-olds who heard short sentences spoken in their native language.
The infants recognized a repeated sentence even after a 14-second interval of silence. The scans showed adultlike activity in the upper region of the brain’s left temporal lobe. The fastest responses were recorded near the auditory cortex, where sounds are first processed in the brain.
Responses slowed down toward the back of the language-processing region and in Broca’s area in the left hemisphere. Activity in that area increased when a sentence was repeated, suggesting that infants may be using a memory system based on Broca’s area just as adults do. These results, reported in the Proceedings of the National Academy of Sciences, demonstrate that the precursors of adult cortical language areas are already working in infants even before the time when babbling begins, Dehaene-Lambertz says.
She offers two possible explanations for these findings. Perhaps certain brain regions are genetically and developmentally “programmed” for language at birth, or even before. Or perhaps these regions are sensitive only to sound or to any rapidly changing sound.
“We do not know yet whether another structured stimulus, such as music, would activate the same network,” Dehaene-Lambertz says. “However, we can say that the processing abilities of an infant’s brain make it efficiently adapted to the most frequent auditory input: speech.”
Edith Kaan, a linguist at the University of Florida, says that researchers are currently studying whether the developing brain handles speech sounds in a different way from other sounds. They also hope to discover how brain regions specialize as children learn to make and understand words, phrases and sentences.
“Eventually, this research may help us understand what capacities are inborn for learning language,” Kaan says. “We may also learn which functions are unique to language and language development, and which are shared with other cognitive activities such as attention, working memory and pattern recognition.”
link
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