Language and Speech

Unit 3 - Lecture 5

productivitiy

ability to produce new signals to represent ideas

overall intelligence theory

normal intelligence = normal theory
issues with theory: genetic condition impairs language or Williams Syndrome

Williams Syndrome

cognitive impairment but good language

specialized brain module theory

built in mechanisms for language acquisition

current theory of evolution of language

language evolved due to selective pressure for social interactions among people and overall intelligence improved as a byproduct

localization

locations within a hemisphere that participate in language-related activities

primary visual cortex

see speech

primary auditory cortex

process sound

angular gyrus

produce sounds (does not understand)

wernicke's area

comprehend sound (formulate an answer)

arcuate fasciculus

path from broca's to wernicke's

broca's area

speech production (commands to use hands/vocal chords); secondary motor cortex

primary motor cortex

understand and produce speech (does the command)

aphasia

deficit in language comprehension or production due to brain damage

broca's aphasia

lesions in Broca's area causes aphasia
- normal comprehension but can't speak or write
- also called nonfluent, production, or expressive aphasia

wernicke's aphasia

damage causes aphasia
- can articulate speech/writing but can't understand words
- words come out as word salad due to lack of comprehension
- also called receptive, fluent, or comprehensive aphasia

dejerine

reading aphasia from damage to left angular gyrus (doesn't convert visual input to sounds)
- no difficulty speaking/comprehension
- alexia & agraphia

alexia

inability to read

agraphia

inability to write

conductive aphasia

damage to arcuate fasciculus causes spontaneous speech to be fluent with many error but there is error awareness with attempts to correct them
- wenicke's area comprehension is working
- arcuate fasciculus connects wernicke's and broca's

anterior lesion effect of damage

expressive aphasia (broca's)

posterior lesion effect of damage

receptive aphasia (wernicke's)

sign language

visual-spatial language involving same cortical areas as comprehension and production of spatial language
- damage to frontal cortex impairs making gestures
- damage to temporal cortex impairs understanding gestures (nonfluent vs fluent aphasia)

dyslexia

reading difficulties

developmental dyslexia

becomes apparent when the affect person is learning to read
heritability = 50%, more common in boys than girls

magnosystem hypothesis

theory to explain developmental dyslexia - processing in dorsal stream of visual system impacted resulting in decreased activation of angular gyrus

acquired dyslexia

dyslexia due to brain damage in angular gyrus