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What is the evolution of the cortex?
Fish:first
reptile:survival instincts (vision, smell, coordination)
first mammal: emotion/instinct (nurture/nocturnal)
Homosapien: explosive growth of cortex (primitive instincts still around)
what are the 6 layers of the horizontal axis columns?
3 input:
layers 1/2: non-specific sensory
layer 4: modality specific from the thalamus
3 output:
layer 3: small/medium cells, short association
layer 5: large, projection and long association
layer 6: variable sizes, projection and long association
What are the three types of interhemispheric white matter?
corpus callosum
anterior commissure
posterior commissure
What are the two parts of the intrahemispheric white matter?
What connects Broca's and Wernicke's areas?
extreme and external capsule
Arcuate Fasciculus
When is hemispheric dominance established?
-no set time
-cerebral dominance is plastic until about 7 years old
-dominance prior to age 2 is Atypical
What gives rise to the brains convoluted appearance and how did it come about?
gyri and sulci
as the neural tube was developing it hit the skull making it fold over onto itself multiple times.
What is lateralization of function?
the brain is NOT symmetrical
complex functions that receive extensive intracortical connectivity appear to become lateralized to one dominant hemisphere. (the two hemispheres differ in capabilities: language or mood)
What does the frontal association area do?
prefrontal cortex: personality, judgement, motor planning
cognitive behavior and motor planning
integrates interoceptive and exteroceptive information
What are the 3 types of projection fibers?
corticopetal: fibers from outside going into cortex
corticofugal: from the cortex to target
internal capsule: largest in cortex
What is apraxia?
deficit in skilled movement without a deficit in strength
How is the cerebral cortex organized?
vertical and horizontal axes
What are the cerebral cortex areas and what do they mean?
specialized: control center for specific functional system
association: integration from specialized areas
what does the parietal association do?
What would a lesion to this area present as?
attention to spacial aspects of sense
language
manipulation of objects in space
apraxia, agnosia, aphasia, body disorder
from lateral to medial put these terms in order and what they are?
external capsule, extreme capsule, insula, claustrum
insula (taste), extreme capsule (white matter: intra), claustrum (visual), external capsule (white matter)
what is surround inhibition?
when one neuron is getting activated more than others it will inhibit the neighboring neurons.
-->one vertical column will use horizontal columns to talk with another (crosstalking) this is vulnerable to seizures
What are the 3 association areas?
Frontal cortex
parietal cortex
limbic cortex
What is intercortical connection?
when 2 different areas are able to "communicate" with one another
what are the categories in the limbic cortex and what do they do?
orbitofrontal and cingulate: emotion
temporal: learning and memory
how is the vertical axis organized?
neuronal columns that are dedicated to individual sensory modalities
What are the cortical functions?
1. language: written or spoken word to convey a message (aphasia)
2. movement: skilled movement (apraxia)
3. perception: know the meaning of stimulus (agnosia)
What are phylogenetic categories based on and what are they?
based on horizontal axis
archeocortex: oldest, 2 layers, hippocampus
paleocortex: old, 3 layers, olfactory cortex
neocortex: newest, 6 layers, most frontal, temporal, parietal, and occipital cortex
What are the intercortical connections?
primary motor and sensory cortex: primary motor cortex and unimodal sensory cortex
higher order cortex: premotor cortex and higher order sensory cortex
association areas: frontal cortex, parietal-temporal-occipital cortex, limbic cortex
What sided stroke is worse and why?
A right hemispheric stroke as they will have left side neglect and are unaware they even have a problem. Will not know there is a left side of their body.
What are the specializations of the left hemisphere?
What are the specializations of the right hemisphere?
-verbal, language, analytical, sequential, detail, rational
-non-verbal, spatial awareness, perceptive, holistic, emotion
What is hemi-neglect and which side is it more common on?
neglect to one half of the body, typically left sided (caused by a lesion to the right side of the parietal lobe)