Cerebral Cortex Flashcards
what is the most highly developed in humans?
the cerebral cortex
what is the weight and thickness of the cerebral cortex?
half brains weight, roughly 1 cm thick but an area of 2 squared feet
what are the layers of the cerebral cortex?
neocortex (95%) 6 layers
paleocortex and archicortex are 3 layers and older phylogenetically
what are the most prevalent neuron cell type in the cortex?
pyramidal cells
pyramidal cells
principle projection neuron, long axons, dendritic spines,, have apical (to the top) and basal (horizontal) dendrites
dendritic spines
on pyramidal cells
- thought to change shape as learning rates are increased (turn synapse efficacy)
- poor spine development can lead to intellectual disabilites (autism, fragile X syndrome)
pyramidal cells
principle projection neuron, long axons, dendritic spines,, have apical (to the top) and basal (horizontal) dendrites, use glutamate and are excitatory
dendritic spines
on pyramidal cells
- thought to change shape as learning rates are increased (turn synapse efficacy)
- poor spine development can lead to intellectual disabilites (autism, fragile X syndrome)
Non pyramidal cells
cortical neurons that are not pyramidal
-short axons, interneurons, remain in cortex, diverse, inhibitory and release GABA
what are some examples of neocortical neurons (nonpyramidal)
basket, candle and bipolar cells
what are the layers of the neocortex?
top to bottom: molecular layer, external granular layer, external pyramidal layer, internal granule layer, internal pyramidal layer, multiform layer
what cell types are in the granular layer?
interneurons, small axons, bunch of small cells
is there white matter in the cortex?
yes
ex. line of gennari
does the neocortex show regional specialization??
YES the somatosensory (postcentral gyrus) projects to nearby cortex so no need for a lot of long axons --> thinner neocortex whereas the motor cortex (precentral gyrus) needs to go down large tracks like the corticospinal tract so more pyramidal cells with long axons -->thicker cortex
does the neocortex show regional specialization??
YES
the somatosensory (postcentral gyrus) projects to nearby cortex so no need for a lot of long axons –> thinner neocortex whereas the motor cortex (precentral gyrus) needs to go down large tracks like the corticospinal tract so more pyramidal cells with long axons –>thicker cortex
***granular and agranular cortex is irregularly distributed
what is different from the broadmans areas that was once thought??
the volume of the cortex is constant, but their is variation among brodmann’s area sizes among individuals. **leads to variation of talents in individuals
what is different from the broadmans areas that was once thought??
the volume of the cortex is constant, but their is variation among brodmann’s area sizes among individuals (more like clouds of area). **leads to variation of talents in individuals
phineas gage
had a pole that went through the frontal lobe of his brain
- *used to think that the brian worked as a whole but now they proved that parts of the cortex are specialized for different functions
- people say phineas lost prefrontal cortex (ventromedial and a little dorsolateral)
phineas gage
had a pole that went through the frontal lobe of his brain
- *used to think that the brian worked as a whole but now they proved that parts of the cortex are specialized for different functions
- people say phineas lost prefrontal cortex
phineas gage
had a pole that went through the frontal lobe of his brain
**used to think that the brian worked as a whole but now they proved that parts of the cortex are specialized for different functions
what are the neocortical regions?
primary sensory (from the thalamic sensory relay nuclei), primary motor that gives rise to the cortical spinal tract, association areas and limbic area
sensory areas of the neocortex
-have a topographical organization that is distorted so that highly sensitive areas like the fingers have large cortical representations
parietal lobe function
- primary somatosensory
- initial processing of tactile and proprioceptive information
- usually the left inferior parietal lobule is involved with language comprehension
- rest of the parietal cortex has spatial orientation and directs attention
occipital lobe function
- primary visual cortex in the banks of the calcarine sulcus
- visual assoication cortex involved in higher order visual processing
temporal lobe function
- primary auditory cortex (transverse temporal gyri)
- auditory association cortex
- language comprehension on dominant side (wernikes)
- higher order visual processing on non-dominant side