Cognitive Neuroscience of Language Flashcards
What are some insights we can get from aphasia?
more arguments about domain generality and domain specificity
What is speech sound categorization?
perceptual narrowing, categorical perception, and the brain
What is the behavioral description of Tan?
-could only produce one jargon syllable seemed otherwise to be in possession of his senses
-in fact seemed to understand what was being said
What was the anatomical description of Tan?
-large lesion
-definitely including the third convolution of the frontal lobe (inferior frontal gyrus)
What is the geschwind-wernicke model of brain and language?
-at the same time as broca’s reports wernicke was observing a different form of language disorder in patients with posterior lesions
-unlike broca’s patients their deficits were more severe for comprehension than for production
-this is a classic double dissociation suggesting that the mechanisms underlying comprehension and production are distinct
What region is involved in wernickes aphasia?
posterior temporal gyrus
How did fmri data formalize structure function relationships in aphasia data?
-the symptoms here are defined very broadly
-a-c shows regions that are likely to be damaged in individuals with fluency deficits
-d-f show regions associated with comprehension deficits
-so data from a large number of patients is consistent with a rough double dissociation where posterior regions are associated with perception whereas anterior regions are associated with production
-note that the insula is a real hot spot for fluency deficits even more so than the cortical broca’s area
What can we think of producing and comprehending as nicely aligned with?
-dorsal and ventral streams
What stream is production related to?
dorsal stream (action)
What stream is comprehension related to?
ventral stream (recognition)
Where does the dorsal stream start and project forward to?
starts in the auditory cortex and projects forward to the motor leanring
What does one view contend the key to language is?
generativity; the core of langauge is the syntactic structure or grammar - all languages have sets of rules for producing grammatical sentences that all users of the language know implicitly
As far as grammar is concerned words or morphemes are what in language?
arbitrary and interchangeable
Where are the words we know stored?
in the lexicon and we learn them explicitly think about the paired associate test for example
What distinction is very important in linguistics?
-the one between grammar and the lexicon is very important
-geschwinds interpretation of the neuropsychological data seemed to suggest that it was also an important organizing principle for language in the brain
What is a lexicon?
set of words you know
What is grammar?
process you use to create sentences
What larger argument did the double dissociation observed in broca and werncikes aphasia become part of?
a larger argument about the modularity of language
What is wernickes aphasia?
word salad with neologisms but syntax is roughly intact
What is brocas aphasia?
telegraphic speech difficulty with word order and grammatical particles (relative sparing of important content words)
What aphasia is problems with lexicon?
wernickes
What aphasia is problems with grammar?
brocas
Why would brocas actual patients not be classified as brocas aphasics?
-they were unable to produce speech at all which means that this is due to motor control issues than premotor issues and they would be classified as suffering from apraxia of speech
What was brocas behavioral descirption of tan?
-could only produce one jargon syllable
-seemed to be in posession of senses
-seemed to understand what was being said
consider:
-the role of dissociations in this argument why is it crcital that leborgne has other senses intact
-why does a capacity for articulate speech soynd like a more plausible function of a particular regions of the brain than criminality or philopopogenitiveness
-if you could examine tan how would u specify his deficits in terms of linguistics - phoenetic phonological lexical syntactic
Why was it interesting to show that Broca’s patients have comprehension deficits?
Broca’s aphasia always has some level of motor dysfunction
-if agramatic speech merely reflects an attempt to communicate despite motor limitations it may be that their syntatcic abilties are intact but they are limited in tehir ability to prodcue sentences for less intersting reasons
-however if we shoe subtle comprehnsuin deficits we can dissociate grammar from lexicon in the brain - just because a brain injury leads to agramatic speeh does not mean that grammar was injured itself
Why do we need psycholinguistic tests to observe grammatical difficulties in comprehension?
-there are alot of redundant cues as to what a speaker intends to say
-alot of language comprehension stakes place in discourse context which clarifies a lot
-maybe brocas patients comprehension depends on these contemporary heruisitics if that were the case you might want to test them with sentences - the dog that the man is biting is mean
How did Caramazza and Zurif test grammar deficits in brocas patients? What did they see?
-made sentences like “the dog that the man is biting is mean” and a set of control sentences
RESULTS
-data from sentence picture matching
-healthy controls at all stimulus types
-wernickes are bad at all due to comprehension deficits
-brocas not good with what did what to whom when syntax conflicted with common sense
-data shows that brocas impatcs syntax