Cerebral Cortex Flashcards
what is the cerebral cortex
vast collection of cell bodies, axons, and dendrites covering the surface of cerebral hemispheres
what is layer III of cerebral cortex
external pyramidal layer
what is layer V of cerebral cortex
internal pyramidal layer
what is the major output neuron of the cerebral cortex
pyramidal cells
is the cortex white or gray matter?
gray
most cerebral cortex has 6 layers except for….
olfactory and medial temporal cortices (they have 3)
what are brodmann’s areas
52 histologic areas in the brain that have specific, functional cortical activity
primary sensory cortex
simple sensory discrimination among intensity and quality of input
primary somatosensory cortex function
discriminates shape, texture, + size of object
primary auditory cortex function
conscious discrimination of loudness + pitch of sounds
primary vestibular cortex function
discriminates head positions and movements relative to gravity
function of secondary sensory cortex
analyze information from primary sensory cortex and thalamus
prim = hear a noise
sec = determine its a dog
secondary auditory cortex function
contrasts sounds heard from memories and categorizes them (noise –> dog barking)
secondary visual cortex function
color + movements + keeping item in center of vision
what area of the brain do S1 and S2 send info to form the highest level of somatosensory processing
posterior parietal cortex (PPC)
posterior parietal cortex (PPC)
sends outputs to motor system ciritical for integration of sensory and motor info, motor planning, and spatial awareness
which cortex area classifies sound
secondary auditory cortex
primary vs secondary visual cortex
prim = light/dark, shapes, size, locations, movements
sec = colors, motions, visual object recognition, spatial awareness, visual fixation
where does the secondary visual cortex project info to
the superior colliculus for visual fixation
secondary visual cortex ventral vs dorsal streams
dorsal = action, through PPC to frontal lobe, adjusts limb movements
ventral = perception, though temporal lobe, recognizes objects
where is the parietotemporal association cortex + what is the function
at junction of parietal, occipital, and temporal lobes
intelligence, problem solving, constructs image of OWN BODY + planning movements
what does the dorsolateral prefrontal cortex do
self awareness
executive functions
what does the ventral and medial dorsal prefrontal association cortex do
both = impulse control, reactions to surroundings, personality
ventral = mood and affect (observable demeanor)
medial = perceives others’ emotions and makes assumptions about them
3 parts of the motor cortex
primary motor cortex
premotor cortex
supplemental motor area
primary motor cortex function (3)
FRACTIONATED MOVEMENT
execution
source of most neurons for corticospinal tract
premotor cortex function (3)
execution and planning
lots of trunk/shoulder girdle neurons
anticipatory postural adjustments
supplemental motor area function (3)
motor planning
movement initiation
planning bimanual and sequential movements
astereognosis
inability to identify objects by touch/manipulation
they can describe the object but cannot identify it
visual agnosias
inability to visually recognize objects despite having intact vision
they can describe object but cannot identify it
prosopagnosia
rare
inability to visually identify people’s faces but can interpret facial expression
a legion where causes astereognosis
secondary somatosensory cortex
auditory agnosia (and what happens L vs R side of brain)
can perceive sounds, but cannot recognize sound
R = environmental sounds
L = speech is affected
anosagnosia
inability to recognize own deficits
stating they can walk when they cannot
homonymous hemianopsia
loss of visual information from one hemifield
optic ataxia
inability to use visual information to direct movements
(even though they can visually identify/describe objects, they cannot shape their movements to fit what they see)
optic ataxia occurs from damage where
dorsal visual stream in parietal lobe
hemineglect is most common where? what type of neglect does it present as?
right parietal cortex
Left sided neglect
why does left sided neglect most often occur
because the right parietal cortex is in control of attention
personal vs spatial neglect
personal = lack of awareness on sensory, personal hygiene/grooming, movement of limbs
spatial = cannot understand spatial relationships, especially with navigation, construction, and dressing
primary motor cortex damage presents as
weakness/paresis
contralateral loss of FRACTIONATED MOVEMENT
dysarthria
motor planning areas (4)
supplementary motor area
premotor area
brocas area
inferior frontal gyrus
motor perseveration
uncontrolled repetition of movement
apraxia/dyspraxia
motor planning deficits
inability to perform sequenced mvmts
constructional motor impairment
interferes with ability to comprehend relationship of parts to the whole
ex: drawing difficulty, assembling, arranging
ideational motor impairment
inability to use objects appropriately, especially when sequence is necessary
ideomotor motor impairment
inability to develop movement sequence, especially to command or mimic activity
gait apraxia
“magnetic” gait, shuffling steps, feet dont lift from floor
4 As of cerebral cortex disorders
Aphasia
apraxia
agnosia
astereognosis
functional neurologic disorders (FND)
cerebral network dysfunction causing speech, motor, sensory, and cognitive changes
not a psychiatric or psychological diagnosis
hoover sign
weak hip extension initially, but then with contralateral sitting hip flexion, hip extensors are strong
4 test findings that are NOT consistent with performance in FMD
hoover sign
give-way weakness
whack-a-mole sign
knee buckling while walking without falling
