Cerebral Cortex I and II Flashcards
What is the function of the cerebral cortex?
Analyzes, plans and initiates response.
Sensory pathways- brings IN information
Reticular system- adjust its level of responsiveness/turns it off or on.
What is the role of pyramidal cells?
- Most of the projection cells out of the brain
- Usually in layer 5
- Long apical dendrite and a basal dendrite
- Use glutamate (excitatory)
- dendritic spines, selectively modified by learning
- 80% of cells in the brain
- found more in agranular layers
What are the neocortical layers?
6 layers that include most of the cortex:
-Agranular with large pyramidal cells and granular areas with small neurons
-
86 billion nerve cells 19% in the cerebral cortex
(most in cerebellum)
What is the role of non-pyramidal cells?
- interneurons of the CC
- 20% of cels in the brain.
- various shapes and appearances
- axons don’t leave the cortex
- use GABA = inhibitory
What are important broadmann areas?
Pre-central: 4
Post-central: 312
Commissural bundles?
l
Association bundles?
= fasciculi
- corticocortical fiber tract connections in the same hemisphere
- Way in which the front communicates with the back
- None are discrete points to point and fibers travel/enter/leave in both directions
- cigulum, sup occipitofrontal fasciculus, sup long fasciulus (arcurate), inf occipitofrontal
arcurate is how brocas and wernkikes areas communicate
What are the neocortical area functions?
- Layer 5: most pyramidal
- Thalamus input usually ends in layers 2, 3, 4
Primary association cortex?
“direct link to the world”
In: thalamic nuclei
out: brainstem and Spinal
primary motor (4) primary somatosensory (312) primary visual (17) primary auditory (41) primary gustatory (ant insula) primary vestibular (p. insula)
Unimodal association cortex?
more complex response function
Loc: adj to 1 areas
Injury could cause agnosia
premotor (6)- larger groups of muscles in an activity
supp motor (6)- posture or using muscles on both sides of the body
somatosensory (5, 7)
visual (18,19 +..)
info is analyzed more deeply, but still having to do with one function.
greater amount of cortex involved
Mulitimodal association cortex?
High level of intellectual fxn
Association areas send convering inputs, may respond to multiple stimuli or under particular circumstances.
Most of the cortex is associated with multimodal associations.
Injury: apraxia (motor) or neglect (sensory)
What is a disconnection syndrome?
White matter damage that interferes with the connection between both hemispheres using the corpus collosum.
ex) alexia without agraphia: cannot read but they can write.
(both sides of the brain can communicate)
What splits the occipital lobe?
The calcarine fissure.
Above the calcarine fissure it processes vision from the lower visual field in the opposite side of the body.
Below, processes visual field from the upper field in the opposite side.
What types of cortex are found in the cerebral cortex?
Neocortex
Archicortex- hippocampus 3 layers
Paleocortex- telencephalon base, olfactory (3-5 layers)
Where would you find more granular cells?
- Post-central cortex
- more non-pyramidal cells than pyramidal.
What is the role of the anterior commissure?
Interconnects temporal lobe and components of the olfactory system.
*temporal lobe
What are the parts of the corpus callosum and what is its function?
Connects mirror images of cortical areas. Genu in frontal lobe anterior body in frontal posterior in parietal splenium in occipital and temporal
note: the brain is not necessary symmetric between the cerebral hemispheres, such that some functions are predominantly on one side or in a different area of the other.
What are the cortical areas taht don’t receive CC commissural fibers?
- Hand area of somatosensory and motor cortex
- Area 17, not including areas adjacent to vertical midline
- temporal lobe connections which travel through the anterior commissure