Biology Reference
In-Depth Information
Figure 2. Simplified schematic of the left side of a human
cerebrum. The four lobes and regions that are generally
associated with certain functions are labeled. The cartoon
figure (called a homunculus) is half in the frontal and half
in the parietal lobe. It provides a point-to-point map super-
imposed on the areas of the brain that process certain sensory
and motor activities on the opposite (right) side of the body
(except for the face, which is largely represented by both sides
of the brain). The part of the homunculus in the frontal lobe
(labeled “moving”) facilitates movements; the part in the
parietal lobe (labeled “sensing”) receives sensory information
about touch, temperature, pain, and body position. Notice
that the hands and feet are all from the right side of the body.
Thus, a pinched right thumb is perceived in the thumb region
near “sensing,” while wiggling the right thumb is facilitated
by the thumb representation in the “moving” region. The
detached structure below the mouth is the tongue. The rep-
resentations of the legs and feet are simplified for illustrative
purposes. Normally, they would extend farther over the edge
into the unseen regions at the top middle of the brain. All of
the labeled activities except speaking are facilitated by both
sides of the brain.
