(23A) Cortex Flashcards
3 layered part of cortex
allcortex
3-5 layered part of cortex
mesocortex
6 layered part of cortecx
isocortex
describe the cellular composition of the 6 layers of the cortex
I = cell poor; GABA interneurons II, III = superficial pyramidal VI = granular V = deep pyramidal VI = polymorphic
What are the primary NTs of the pyramidal cells? Are the bipolar or multipolar? spiny or aspiny?
excitatory = glu, asp
bipolar (usually projection)
spiny
What are the primary NTs of the nonpyramidal cells? Are the bipolar or multipolar? spiny or aspiny?
inhibitory = GABA
multi or bi polar but are local interneurons
aspiny
nonpyramidal, multipolar cells that have terminations that surround the somas of pyramidal cells
basket cells
nonpyramidal, multipolar cells that have terminations that contacts the initial segment of pyramidal cells
chandelier
what subtype of nonpyramidal cells innervatet he more distal dendrites of pyramidal neurons
bipolar/bi-tufted
what is the main extrinsic input to the cortex?
thalamus > widely ptojecting brainstem nuceli (which is modulatory)
what layer of the cortex does specific thalamic input project to?
IV
What later do non-specific thalamic inputs project to?
I
What are the cortical inputs that project to ipsilateral cortex called? what layer of cortex are they found?
association fibers; II, III
What are the cortical inputs that project to contralateral cortex called? what layer of cortex are they found?
callosal projections; II and III
Where do pyramidal cells in cortex layers V and VI project?
superficial V = contralateral cortex or striatum
deep V = beyond telenchephalon (pons, brainstem, spinal cord)
VI = thalamus (same area that afferents came from)
**note I and IV receive inputs from non-specific and specific thalamic nuclei respectively
Thalamocortical rhythms are observed on
EEG
Why are chandelier cells powerful regualators of cortical output?
they synapse as AIS and therefore will determine the final size of the AP
Why are basket cells powerful regualators of cortical output?
they are acting at soma and therefore will mooulate the signal leaving the body to the axon
describe how a signal gets to and leaves the cortical column
comes in from thalamus to layer I or IV where they synapse with dendrites of cells that originate in layer II or III. these cells send their axons to layers V or VI to go to subcortical area of interest
how does the cortical histology vary from motor to sensory cortex?
motor: little IV and big V; agranular
sensory: big IV and little V; granular
brodman’s areas for primary motor and where is it found?
4
precentral
brodman’s areas for primary sensory and where is it found?
3, 2, 1
postcentral, superior parietal lobule
brodman’s areas for primary visual and where is it found?
17
banks of calcrine fissure
brodman’s areas for primary auditory and where is it found?
41, 42
transverse gyri
in general what happens in the assocaition areas
unimodal inputs get combined to paint a bigger picture of what is going on
example of unimodal motor assc area (and Brodman #)
pre motor = 6
example of unimodal somatoesthesis assc area (and Brodman #)
5 and 7
describe where a somatosensory afferent from the VPL will go for processing in the cortex
VPL → 3, 2, 1 (parallel processing) → 5, 7 → heteromodal area to combine
What is an evoked potential
mapping out somatosensory pathways by electrically stimulating surface of head and waiting in EEG for changes in specific area that controls it
What may cause phantom limb?
cortical reorganization; due to loss of input after amputation, adjacent cells in the cortex take over the area that was previous devoted to the amputated limb and can result in referred sensations
assc cortex that is imp for being able to pay attention
parietal assc cortex
assc cortex that is imp for being able to name things
temporal
assc cortex that is the overall executive of behavior
prefrontal
= RIO = restriant, initiative, order and gives you sense of self
assc cortex that is primarily involve in visual system
occipital
assc cortex that primarily received input from pulvinar
parietal and occipital = attention and vision
assc cortex that primarily received input from LP nucleus of thalamus
temporal = name things
assc cortex that primarily received input from medial dorsal nucleus
prefrontal = execute behaviors
effect of damage to paretal assc cortex on dominant side? non-dominant side?
dominant side = language disorder
non-dominant = sensory neglect (ignore everything fond on contralateral side relative to the injury)
effect of damage to temporal assc cortex
inability to recognize objects and people
effect of damage to prefrontal assc cortex
personality changes and inability to plan
responsible for providing your working memory
dorsolateral prefrontla cortex
