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Chapter 10
Front
Top view
Back
Occipital
lobe
Parietal
lobe
Frontal lobe
Right
hemisphere
Left
hemisphere
Primary
motor
cortex
Somato-
sensory
cortex
Central
sulcus
Right
hemisphere
Arm
Head
Cross-sectional view
Leg
Trunk
Figure 10–11
Somatotopic map of major body areas in primary motor cortex. Within the broad areas, no one area exclusively controls the movement of a single
body region, and there is much overlap and duplication of cortical representation. Relative sizes of body structures are proportional to the number
of neurons dedicated to their motor control. Only the right motor cortex, which principally controls muscles on the left side of the body, is shown.
Supplementary
motor cortex
Supplementary
motor cortex
Primary motor
cortex
Primary motor cortex
Premotor
area
Somatosensory cortex
Somatosensory
cortex
Parietal-lobe
association
cortex
Parietal-lobe
association
cortex
(a)
(b)
Figure 10–10
(a) The major motor areas of cerebral cortex. (b) Midline view of the right side of the brain showing the supplementary motor cortex, which
lies in the part of the cerebral cortex that is folded down between the two cerebral hemispheres. Other cortical motor areas also extend onto
this area. The premotor, supplementary motor, primary motor, somatosensory, and parietal-lobe association cortexes together make up the
sensorimotor cortex.
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