Higher Cortical Functions Flashcards
assigned functions and cortical regions
pre- and post-rolandic zones: motor and sensory activities
striate occipital zones: visual perception
superior temporal gyri: auditory
two cell types that predominate in the neocortex
pyramidal cells (large) rounded (granular) cells (smaller and more numerous)
two main types of neocortex
homotypical: six layers can be seen
heterotypical: has association cortex (large areas not committed to any functions)
locations of the granular cortex
primary sensory cortex
postcentral gyrus
banks of the calcarine sulcus
transverse gyri of heschl (layers 2 and 4 are developed for afferent impulses)
what are giant cells of betz
largest cells of the granular cortex
gives rise to some of motor fibers in CST
locations of agranular cortex
frontal motor cortex (precentral cortex: areas 4 and 6)
layer 5
how to distinguish agranular cortex
more pyramidal than granular cells, especially in layer 5
four general functional categories of the brain
sensory
motor
unimodal association cortex
multimodal association cortex
projections of the sensory nerves
thalamocortical fibers -> primary sensory areas
ventral posterior complex (thalamus) -> primary somatosensory cortex (PCG)
lateral geniculate nucleus -> primary visual cortex
medial geniculate nucleus -> primary auditory cortex
motor function: _____ tract
sensory function: ___ tracts
motor: descending CST
sensory: ascending spinothalamic and dorsal column medial lemniscus
function of unimodal association areas
devoted to higher level of information processing via corticocortical fibers
locations of unimodal association areas
visual unimodal association cortex: visual cortex
somatosensory association cortex: posterior to post-central gyrus
auditory association cortex: superior temporal gyrus next to primary auditory cortex
function of multimodal association areas
coordinate farther regions
- communication with language
- reasoning
- extrapolating future events based on present experience
- making complex and long range plans
- imagination
basic flow of afferent and efferent stimuli integration
primary sensory cortex (afferent stimulation)
unimodal sensory association areas (nearby)
multimodal sensory association areas (more than one sense)
multimodal motor association area
premotor area (planning)
primary motor cortex (implementation)
cerebral hemisphere that controls language
dominant hemisphere (usually left)
t/f almost all right handed individuals and half of left handed individuals are left cerebral dominant
true
what is wada test
to test for hemisphere dominance
- inject sodium amytal into internal carotid artery
- produce arrest of speech for 30s in dominant side
- important before temporal lobectomy for epilepsy
responsible for the motor cortex (contralateral movement of the face, arm, leg, trunk)
precentral gyrus
serves as the expressive center for speech in the dominant hemisphere
broca’s area
area for contralateral head and eye turning
supplementary motor area
for cortical inhibition of bladder and bowel voiding
paracentral lobule
result of impairment in precentral gyrus
monoplegia or hemiplegia
result of damage to broca’s area
broca’s dysphasia
result of damage to supplementary motor area
paralysis of head and eye to opposite side (head turns towards diseased hemisphere and eye look in the same direction)
result of damage to pre-frontal areas
orbitofrontal syndrome frontal convexity syndrome medial frontal syndrome primitive reflexes disturbance of gait (apraxia) resistance to passive movements of the limbs
symptoms of orbitofrontal syndrome
disinhibition
poor judgment
emotional lability
symptoms of frontal convexity syndrome
apathy
indifference
poor abstract thought
symptoms of medial frontal syndrome
akinetic, incontinent, sparse verbal output
result of damage to paracentral lobule
urine and fecal incontinence
expressive center for speech
supramarginal and angular gyri of the dominant hemisphere
dominant vs non-dominant parietal lobe functions
dominant: calculation
non-dominant: body image, awareness of external environment, visual/proprioceptive skills
result of damage to sensory cortex
postural sensation, passive movement, and accurate localization of light touch disturbed
discrimination between one and two points lost
difficulty in appreciation of size, shape, texture, and weight
perceptual rivalry
Gertsmann’s syndrome on non-dominant side
anosognosia (unaware of opposite side)
dressing apraxia
geographical agnosia
constructional apraxia
Gertsmann’s syndrome on dominant side
finger agnosia
acalculia
agraphia
result of damage to optic radiation in parietal lobe
lower homonymous quadrantanopia
function of auditory cortex
dominant: hearing language
non dominant: hearing sounds, rhythm, music
function of middle and inferior temporal gyri
learning and memory
function of limbic lobe
olfaction and emotional behavior
incorporation of inferior frontal and medial parietal structures
result of damage to auditory cortex
cortical deafness auditory hallucinations (temporal lobe disease)
result of damage to optic radiation in temporal lobe
upper homonymous quadrantanopia
result of damage to limbic lobe
olfactory hallucination with complex partial seizure
result of damage to middle and inferior temporal gyri
disturbance of memory/learning
primary visual cortex (perception of vision)
striate cortex
association visual cortex
parastriate cortex
result of damage to striate cortex
extensive bilateral cortical lesions = cortical blindness
anton’s syndrome
involvement of striate and parastriate cortices
- damaged interpretation of vision
balint’s syndrome
bilateral parieto-occipital lesions = inability to direct voluntary gaze
associated with visual agnosia
