Language and Brain

[Antara11]

Brain is divided into two hemispheres: the left and right hemispheres.The hemispheres are connected by bundle of nerve fibers: the corpus callosum.

Contralateral control: Each hemisphere controls opposite side of body
Left hemisphere controls right side of body
Right hemisphere controls left side of body

[Antara11]

Lateralization: the brain is asymmetrical such that each hemisphere is specialized for certain cognitive functions.

Left hemisphere:
Analytical processing (analyzing information)
Language, speech sounds
Mathematics
Temporal relations
Intellectual reasoning


Right hemisphere:
Holistic processing (recognizing overall patterns, e.g., face recognition)
Nonspeech sounds
Music
Visual-spatial skills
Emotional reactions

[Antara11]

Split-Brain patients

Corpus callosum is severed (used to treat cases of epilepsy)
Two hemispheres cannot communicate with each other

Left hemisphere: Language
Aphasia:
Any language deficit caused by damage to the brain (e.g., bullet, stroke, infection, etc.)
Aphasia almost always caused by left hemisphere damage

Broca’s area: organizes articulatory patterns of language; also controls use of inflectional, function morphemes

Wernicke’s area: involved in comprehension and selection of words from mental lexicon

[Antara11]

Broca’s aphasia: Labored, halting speech
Lack of inflections and function morphemes
Comprehension is generally good

Ex. “Cookie jar… over … chair… water… empty…ov…ov…[Examiner: ‘overflow’?] Yeah.”


Wernicke’s aphasia: Speech is fluent (i.e., can use function words, inflections) but semantically incoherent
Lexical errors, nonsense words, circumlocutions
Comprehension is poor

Ex. “Well, this is…mother is away here working out o’here to get her better, but when she’s working, the two kids looking in the other part. One their small tile into her time here. She’s working another time because she’s getting, too.”

Aphasia in ASL users
Broca’s: sign slowly, omit inflections
Wernicke’s: sign fluently but confusingly, show comprehension problems