Neuro Ch 11 Language and Laterisation

  1. language
    medium to communicate complex ideas by encoding them in a series of arbitrary symbols according to a system shared by communicating individuals
  2. speech
    • vocal form of human communication
    • production of sequences of phonemes comprising words and sentences to convey concepts and ideas
  3. aphasia
    • language functions are lateralised to the left hemisphere of the brain for most people 
    • aphasia is the impairment or loss of language skills caused by brain damage (usually to the left hemisphere)
  4. Broca's Aphasia
    • can understand but can't talk, word finding difficulty 
    • expressive aphasia: disorder of language function that involves the loss of the ability to produce language with intact ability to comprehend language
  5. Wernicke's Aphasia
    • can't understand but can make meaningless speech (damage to left superior temporal gyrus)
    • receptive aphasia: impaired ability to receive and comprehend language 
    • aka fluent aphasia because speech seems fluent
    • word salad: nonsensical string of words
    • neologisms: invented meaningless words
    • paraphasia: substitute incorrect word for correct one
  6. Wernicke-Geschwind model
    • A. input from A1 to Wernicke's area, about spoken words
    • B. input from V1 to Wernicke's area, about written or signed words 
    • C. signals from Wernicke's area sent to Broca's area, via the arcuate fasciculus
    • D. signals from Broca's area sent to motor cortex to coordinate spoken or written (or signed) response
  7. Wernicke's Geschwind model is over simplified
    • more than one route from Wernicke's area to Broca's area. There is also a route via left inferior parietal lobule
    • damage to areas outside of those in the W-G circuity can produce aphasias
    • isolated damage to Broca's area produces only a temporary aphasia; damage that includes Broca's area underlying white matter and neighbouring structures lead to a more permanent aphasia
  8. conduction aphasia
    preserved language comprehension and production; impaired ability to repeat words
  9. global aphasia
    • all aspects of language are impaired, including comprehension, repetition, and production
    • damage to lateral regions of the left hemisphere occurs
  10. left hemisphere functions
    • fine motor control 
    • apraxia: difficulty performing skilled movements when asked to do so
  11. right hemisphere functions
    • more involved in spatial functions
    • also more invovled in understanding emotion, including perceiving facial expressions and moods
    • processing music and melodies
    • pocesses prosody of language (its stresses, intonations, rhythm)
  12. note on laterization
    almost every part of brain (except pineal gland) is bilateral: two copies, one in each hemisphere
  13. corpus collosum
    • hemisheress are connected by bundles of axons that cross the midline of the brain, allowing communication between its halves
    • the largest of these white matter tract is the corpus callosum
  14. callosotomies
    • severing corpus collusum to prevent seizure transmission and communication between the hemispheres
    • leads to split brain
  15. split brain patients
    patients appear to have two brains: each hemisphere can lead and perform tasks independently from the other (even simutaneously with it)
  16. parse (stream of speech)
    • divide up the incoming signal into discrete words
    • language learning depends on both experience and innate predispositions
  17. parentese
    baby talk
  18. language learning from experience
    • slowed articulation and higher pitch of parentese produce clearer signal for the infant's brain to capture and interpret 
    • babies prefer parentese to normal adult voice (same with learning foreign language)
  19. statistical learning
    • learning regularities in the transitions between stimuli 
    • infants quickly learn phoneme characteristics of their native language and by 9 months prefer it over others
  20. babies and sound
    • start life with capacity to hear all possibe sounds, then lose at learn native tongue 
    • learn to identify sound that carry meaning in their native language and no longer discriminate differences not important in that language
  21. universal grammar
    an innate set of grammatical rules that infants are born with
  22. poverty of the stimulus
    • children do not hear a broad enough sample of language to learn grammar purely from experience
    • absence of negative evidence (sentences that do not make sense in the language or are incorrectly constructed)
Card Set
Neuro Ch 11 Language and Laterisation
cognitive neuroscience