cerebral cortex Flashcards
areas of cortex
cerebral cortex has:
- primary areas
- unimodal association areas
- heteromodal association areas (modalities combine: involve attention, memory, planning)
primary areas include
- primary motor cortex
- primary sensory cortices (somatosensory, visual, auditory)
unimodal association areas include
- premotor cortex
- secondary sensory areas
heteromodal association areas include
- parietal-occipital-temporal areas
- prefrontal areas
- inferior temporal areas
apraxia
loss of the ability to carry out a certain motor action despite the absence of paralysis or weakness
- basically do opposite of what you want to do
- can’t plan out the motion
agnosia
the loss of the ability to recognize things despite normal sensation
lesion of motor cortex causes
contralateral spastic paralysis
location of premotor and supplementary motor areas
lesion of supplementary motor area causes
apraxia
how to test for a lesion of the supplementary motor area
- use a key
- wave goodbye
- salute the flag
- blow a kiss
- hammer a nail
- brushing teeth
- opening a bottle of soda
- pouring water into a glass and drinking it
location of somatosensory cortex
in parietal lobe
lesion of somatosensory cortex causes
trouble recognizing touch, sound, taste, etc.
lesion of parietal lobe causes
- tactile agnosia
- finger agnosia
- tactile apraxia
tactile agnosia
- close eyes, object in hand
- cannot tell you what it is
- no recognition of 3D object
finger agnosia
- closed eyes, move fingers
- can’t tell you which finger is moving
- can’t move a finger specifically on command
tactile apraxia
- blindfolded , something in hand
- cannot tactilely explore an object
lesion of primary visual cortex causes
field blindness
if one lateral geniculate or one occipital cortex is affected you get:
field blindness
lesions of visual association area causes
- dorsal: loss of seeing movement (ex: can pour water but cannot see water moving into cup)
- ventral: loss of color perception (only blakc and white)
- cannot recognize faces
lesion of area 19 on cortex causes
achromatopsia (lack of color vision)
lesion of inferior temporal association cortex causes
prosopagnosia (cannot recognize faces)
lesion of broca’s area causes
- expressive aphasia (deficit of language and not understanding words - not speech)
- cannot express words
- even people using sign language cannot communicate effectively
lesion of wernicke’s area cause
- receptive aphasia
- speak all the time but speak nonsense and gibberish (trouble with speech not understanding)
speech circuit
sees word > primary visual cortex > angular gyrus > Wernicke’s area > white matter > Broca’s area > motor cortex> articulation of the word that was read
receptive aphasia
- speech is fluent but nonsensical
- use of wrong words and jargon
- failure of comprehension
- defective repetition
- logorrhea
lesion of angular gyrus causes
unable to read
dominant hemisphere
- right hand = left hemisphere dominant
- left hand = right hemisphere dominant
- 50% of left handed people are also left hemisphere dominant
left hemisphere contains
language
whichever hemisphere contains speech is considered
dominant
function of non-dominant hemisphere
- gesture, emphasis and emotional aspects of speech
- spatial relationships
- musical ability
- lesion: contralateral neglect`
neglect syndrome
- show patient image and ask to reproduce
- neglect left side of image and only draws right
- thus lesion of non-dominant hemisphere
lesion of prefrontal cortex impairs
- planning
- decision making
- cognitive control
Phineas Gage
prefrontal cortex lesion
prefrontal cortex lesions cause:
impaired:
- planning
- decision making
- cognitive control
Case 1:
- before: salesman sn sold stuff in stores
- after: personality change
Case 2:
- before: military man
- after:
impairments associated with prefrontal cortex:
- impaired attention
- poor working memory
- executive functions (planning) poor
- poor fine movement
- self control impaired
- abstract thinking impaired
- blunted or inappropriate affect
- little concern about sphincter control
how can you stop the spread of epileptic seizures to the other hemisphere?
cut the corpus callosum
what does it mean to have split brain?
- separation of hemispheres by split of corpus callosum
what happens with people who have a split brain?
- typically: image shown on left goes to right side cortex and passes to the left hemisphere through corpus callosum
- split brain: image shown on left then goes to right side cortex but does not go to left side because of the loss of connection
- they cannot vocalize what it is, but can ID the object
With a split brain,
