Cerebral Cortex

2022-01-24 links: Neuroanatomy reference:

Cerebral Cortex #

The entire outer layer of the cerebrum (aka telencephalon). A general pattern is the lateral surface being for calculating, cognitive function, and medial surfaces being more involved in emotion/motivation.

Layers #

• Great video on PFC layers https://www.youtube.com/watch?v=x2mYTaJPVnc
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  • (This is far from comprehensive, especially on a region by region basis. But maybe a little flashbulb memory of this wouldn’t hurt) Divded first into the neocortex, from the outermost inwards: (Then there’s the allocortex, which is just 10% of the CC’s area.)
• I: Molecular layer. Not very dense. Mostly random neurites I guess. Perhaps it is waiting for evolution to fill it.
  • Mainly receives input from the Thalamus (M-type cells)
• II: External granular layer. Mostly Stellate Cells and small pyramidal neurons.
  • Receiver of cortical (callosal and association) afferents.
• III: External pyramidal layer. Obviously: Pyramidal cells.
  • Small and medium? Large? Not sure.
  • Main source of corticocortico efferents
• IV: Internal granular layer. Non-pyramidal cells, mostly Granule Cells, like densly packed Stellate Cells.
  • Receives (excitatory) input from C-type thalamus layers: Viewpoint: the core and matrix of thalamic organization
• V: Internal pyramidal layer. Medium-large pyramidal cells.
  • This layer contains betz cells.
  • Efferents towards the neostriatum, brainstem, and spinal cord.
• VI: Polymorphic/multiform layer. Many cell types like pyramidal and stellate.
  • Reciprocal connection with the thalamus.

• The supraganular layers are the principal targets of interhemispheric corticocortical afferents, and for brainstem monoaminergic neurons.

Cell Types #

~85% excitatory and 15% inhibitory neurons.

• 2/3 of neurons in the CC are pyramidal neurons.
• The remaining 1/3 are Stellate Cells. Then it’s a mix of stuff like basket cells