Cerebral Cortex I Flashcards
What does the cerebral cortex do?
Analyzes, plans, and initiates response. Receives information via sensory pathways. Reticular system adjusts level of cerebral cortex responsiveness.
How many layers does the neocortex have?
6 layers. Things leaving (pyramidal cells) tend to be in deep layers. Non-pyramidal cells tend to be in superficial layers.
What are pyramidal cells?
Long apical dendrite and a basal dendrite. Axons leave cortex and release glutamate (excitatory). Have dendritic spines, which are selectively modified by learning.
What are non-pyramidal cells?
Interneurons of the cerebral cortex. Axons do not leave the cerebral cortex and release GABA (inhibitory). Various shapes and appearances.
What are the brodmann areas for pre and postcentral gyri?
Precentral gyrus = area 4, motor
Postcentral gyrus = area 3,1,2, somatosensory
What brodmann areas are associated with motor, somatosensory, visual, and auditory functions?
Motor = precentral gyrus, 4 Somatosensory = postcentral gyrus, 3, 1, 2 Visual = calcarine, 17 Auditory = transverse temporal gyrus, 41
Define commissural and association bundles
Corpus callosum connects left and right cerebral cortex: genu, body, splenium. Temporal lobes are connected by anterior commissure.
Association bundles are corticocortical conenctions in the same hemisphere. Fibers travel in both directions, entering and leaving.
Describe unimodal association areas.
They are adjacent to primary cortical areas, do the same function (but less precise). Injury can cause agnosia.
Premotor and supplementary motor: 6
Somatosensory: 5, 7
Visual: 18, 19
Describe multimodal association areas.
High level intellectual functions. Injury can cause apraxia (motor) or neglect (sensory). Three multimodal association areas: 1) parietooccipitaltemporal region: injury to right side causes contralateral neglect. Injury to left side causes apraxia. 2) Prefrontal area: working memory and decision making. 3) Limbic area: emotional and “drive” related behaviors. Most of brain dedicated to doing higher level stuff
Define a disconnection syndrome
All cortical areas receive CC commissional fibers, EXCEPT temporal lobe, which is connected by anterior commissure. Disconnection syndromes often result from white matter damage that interferes with CC commissural connections. E.g. Alexia without Agraphia: can’t read but can write
Explain Alexia without Agraphia
Can’t read but can write. Damage to corpus callosum in area preventing communication betwen occipital lobe and Wernicke’s area.
Injury to what causes agnosia?
Injury to unimodal association areas
Injury to what causes apraxia?
Injury to multimodal association areas
Injury to what causes neglect?
Injury to multimodal association areas
