Lecture 2: Forebrain - cerebral cortex

Question 1

Efferent fibres of the cortex?

Answer 1

Projection fibres (V) - corticofugal

Association and commisural fibres (III)

Question 2

Layer II?

Answer 2

External granular

Small granular neurons (8-20microns)

sensory input from other areas of the brain

Question 3

Layer III

Answer 3

external pyramidal

10-40 mircons thinck

Info to other areas of the cotex

Question 4

Layer IV

Answer 4

Internal granular

larger granular cells recieving most of the sensory info from the peripery

Question 5

Layer V

Answer 5

Internal pyramidal

large (60-120microns) motor neurons froming the pyramidal tract kown as BETZ CELLS

UPPER MOTOR NEURON

Question 6

Layer VI

Answer 6

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

Question 7

Afferent fibres of the cortex?

Answer 7

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

Question 8

Major types of cerebral cotex?

Answer 8

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