Primary motor cortex

Question 1

Localization

Answer 1

• frontal lobe Area 4
• precentral gyrus
• paracentral lobule (anterior part)

Question 2

Function

Answer 2

commands for execution of movements

Question 3

Characteristic features

Answer 3

• agranular cortex (Betz cells; giant pyramidal cells)

- topographical organization (motor homunculus) -> muscles of hand and speech occupy significantly larger areas

Question 4

Afferents to primary motor cortex

Answer 4

• thalamus VPL (cutaneous afferent); VPS (proprioceptive info)
• cerebellum – thalamus VLp
• basal ganglia – thalamus VLa
• premotor cortex
• Activity of upper motor neurons is under
  continuous modulation by sensory signals

Question 5

Efferents from primary motor cortex

Answer 5

• internal pyramidal layer (V layer) – pyramidal cell axon->
• > corticospinal tract
• > corticonuclear tract (corticomesencephalicus, corticobulbaris)