Lecture 2: Forebrain - cerebral cortex Flashcards
Efferent fibres of the cortex?
Projection fibres (V) - corticofugal
Association and commisural fibres (III)
Layer II?
External granular
Small granular neurons (8-20microns)
sensory input from other areas of the brain
Layer III
external pyramidal
10-40 mircons thinck
Info to other areas of the cotex
Layer IV
Internal granular
larger granular cells recieving most of the sensory info from the peripery
Layer V
Internal pyramidal
large (60-120microns) motor neurons froming the pyramidal tract kown as BETZ CELLS
UPPER MOTOR NEURON
Layer VI
Multiform layer
least clear function, is a mixture of granular and pyramidal the same ratio that is between II and V
some integration of sensory input
Afferent fibres of the cortex?
Specific afferent (IV) - corticopetal - said to be the granular layer dividing infra and supra-granular
Association and commissural afferents (I, II, III) - Said to be the supragranular layer
Major types of cerebral cotex?
Heterotypical
- mostly one cell type (agranular or granular)
- Eg. 1˚ motor cotex = agranular
Homotypical
- Most of the cortex appears as this
- an even mixture of pyramidal and granular