Cortex Flashcards
what is major input to prefrontal cortex?
mediodorsal thalamus
characterized by layers, pattern of distribution of cell bodies in cortex
cytoarchitecture
emotion conveyed by tone of voice; what hemisphere is this located?
prosody; right
what functions are typically associated with left hemisphere?
language, praxis, arithmetic (calculating/analytical) and musical ability (analytical skills), sense of direction (following directions)
what functions are typically associated with right hemisphere?
prosody, spatial attention, arithmetic (line up columns of numbers), musical ability (untrained), sense of direction (sense of spatial orientation)
what results as lesion of non-dominant hemisphere?
hemineglect
part of allocortex…afferents from septal areas, first in evolution; what makes up this?
archicortex; hippocampus and limbic cortex
part of allocortex…makes up 3-5 layers, afferents from olfactory areas (basal olfactory structures, entorhinal, periamygdaloid areas)
paleocortex
these were two pioneering doctors in split brian research
Sperry and Gazzaniga
which hemisphere acts as interpreter (tries to make sense of what it’s seeing)
left
what is lesion in Gerstmann syndrome? what blood vessels is commonly involved?
dominant parietal lobe; PCA
right/left confusion, finger agnosia, dysgraphia, dyscalculia, R hemianopia (unrelated, but optic radiations commonly affected)
Gerstmann syndrome
these make up the internal granular layer; what does it receive projections from?
spiny and smooth stellate neurons; VPL and VPM, LGN (only in striate)
what fibers come from internal pyramidal layer? what cells are located in this area?
corticobulbar, corticospinal, corticostriatal fibers; Betz cells
multiform layer is major source of these fibers
corticothalamic
horizontal myelinated fiber bundles in lamina IV and V make these
bands of Baillarger
what are general symptoms of Gerstmann’s syndrome?
agraphia, acalculia, r/l disorientation, finger agnosia
what hemisphere is typically in involved in prosopagnosia?
right
this fiber bundle is affected if can’t communicate between Wernicke’s and Broca’s
arcuate fasicuclus (SLF)
basically word blindness…write but not read (language areas cut off from visual input)
alexia (w/o agraphia)
blood vessel involved in alexia w/o agraphia
PCA
three domains involved in frontal lobe function
restraint, initiative, order
prefrontal lesion….apathy, lifeless, abulic state; no personality, lack initiative, no focus
dorsolateral lesion
prefrontal lesion (common in criminals)…impulsive, emotionally disinhibited, poor judgement/irritability/euphoria
orbitofrontal lesion
prefrontal lesion…depression life symptoms
left frontal
prefrontal lesion….associated with mania
right frontal
these are frontal release signs that are normally suppressed in development
suckling and grasp reflex
thalamocortical inputs to frontal lobe
dorsomedial and anterior nuclei
thalamocortical inputs to primary somatosensory cortex (3,1,2)
VPL/VPM
thalamocortical inputs to occipital and temporal lobes (17-22, 36-38, 41, 42)
pulvinar
thalamocortical inputs to primary visual cortex (area 17)
LGN
thalamocortical inputs to primary auditory cortex (41, 42)
MGN
thalamocortical inputs to limbic lobe (area 23-31, 33-35)
anterior nucleus
unimodal association cortex for visual association located in what areas?
18, 19, 20, 21, 37 (visual association cortex)
unimodal association cortex for somatosensory located in what area?
5
unimodal association cortex for auditory association located in what area?
22
unimodal association cortex for premotor and supplementary motor located in what area?
6
unimodal association cortex for frontal eye fields located in what area?
8
association cortexes that are multimodal
prefrontal, parietal, and temporal
out layer of horizontal myelinated fiber bundles in lamina IV and V in primary visual cortex
stria of Gennari
what are output cells of cortex? what layers are these located in?
pyramidal cells; II, III, V
NT for pyramidal cells
glutamate
giant cells of Betz are located exclusively in this area
motor cortex
are stellate cells (*layer 4*) excitatory or inhibitory?
excitatory
these make up the local circuit of interneurons with pyramidal cells
stellate, basket, Retzius-cajal cells and cells of Matinotti
SLF bundle connects these structures
frontal, parietal, occipital
arcuate bundle connects these structures
frontal and temporal
inferior occipito-frontal fasciculus bundle connects these structures
occipital and frontal
uncinate fasciculus connects these structures
frontal and temporal
cingulum bundle connects these structures
frontal, parietal, occipital, temporal
arcuate loop connects these structures
adjacent gyri
thalamus projects primarily to this layer
IV
efferent fibers of pyramidal axons typically come from these layers
V and VI
primary sensory cortex is granular or agranular? what layer of sensory cortex is thickest?
granular; layer IV
primary motor cortex is granular or agranular? what layer of motor cortex is thickest?
agranular; layer V
these are multimodal association cortices
prefrontal, parietal and temporal association cortex
this determines cerebral dominance
Wada test
lesion to these areas will produce Broca’s aphasia (expressive); what blood vessel may be implicated?
44, 45; MCA (could also see contra motor)
blood vessel and additional structure that are compromised in Wernicke’s aphasia
MCA and possibly Meyer’s loop
characterized by alexia, agraphia, word salad (no fluent speech), *unaware of disability*
Wernicke’s aphasia
this is interrupted in conduction aphasia; what does this structure connect?
uncinate fasciculus; Broca’s and Wernicke’s areas
what is blood vessel involved in global aphasia (Broca’s and Wernicke’s)
ICA or MCA (M1)
lesion here will cause alexia without agraphia; what blood vessel is involved usually?
dominant occipital cortex; PCA
what is prevented in dominant occipital cortex lesion (alexia without agraphia)? what does this cause?
processing visual info from R hemifield; R hemianopia
lesion here causes alexia WITH agraphia
inferior parietal lobe
what are symptoms of Gerstmann’s syndrome? what part of cortex is affected?
agraphia, acalculia, R/L disorientation, finger agnosia; inferior parietal lobule/angular gyrus
nondominant hemisphere is responsible for this
attention and visual-spatial gestalt
lesion of nondominant hemisphere will result in this in regards to attention
contralateral hemineglect
inability to recognized left side of body (lesion of nondom hemisphere)
asomatognosia
inability to negotiate familiar surroundings (lesion of nondom hemisphere)
topographic memory loss
lesion of dom or nondom hemisphere will cause loss of affect…cant appreciate humor
nondominant
this comprises 1/3 of cerebral cortex
frontal lobes
area for premotor cortex; postural adjustment for skilled movement (FEF also located here)
6
located on medial surface in front of primary motor area….*micturition center*
supplementary motor center
these make up motor areas of frontal lobe
primary motor, premotor, supplementary motor, limbic lobe, prefrontal cortex
this responsible for integration of multimodal sensory, motor, limbic information (*heteromodal association cortex*)
prefrontal cortex
functions of frontal lobes
restraint, initiative, order
this allows for shifting of attention, adaptability, see options, ‘go with the flow’
cingulate gyrus
problems with this causes addictive behavior, obsessions/compulsions, argumentative, worrying, OCD, eating disorder
cingulate gyrus
