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cerebral cortex

Wednesday 28 May 2003

Cortical layers

- The molecular layer I, which contains few scattered neurons and consists mainly of extensions of apical dendrites and horizontally-oriented axons; some Cajal-Retzius and spiny stellate neurons can be found.

- The external granular layer II, which contains small pyramidal neurons and numerous stellate neurons.

- The external pyramidal layer III, which contains predominantly small and medium-size pyramidal neurons, as well as non-pyramidal neurons with vertically-oriented intracortical axons; layers I through III are the main target of interhemispheric corticocortical, and layer III is the principal source of corticocortical efferents.

- The internal granular layer IV, which contains different types of stellate and pyramidal neurons, and is the main target of thalamocortical afferents as well as intra-hemispheric corticocortical afferents.

- The internal pyramidal layer V, which contains large pyramidal neurons (such as the Betz cells in the primary motor cortex); it is the principal source of subcortical efferents.

- The multiform layer VI, which contains few large pyramidal neurons and many small spindle-like pyramidal and multiform neurons; layer VI sends efferent fibers to the thalamus, establishing a very precise reciprocal interconnection between the cortex and the thalamus (Creutzfeldt, 1995).

Layers

- MZ
- CP
- IZ
- SVZ
- VZ

Anomalie

- cortical atrophy

See also

- Brain
- cortical neurogenesis

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