Nervous System II
Both cerebral hemispheres participate in basic functions,
such as receiving and analyzing sensory impulses, control-
ling skeletal muscles on opposite sides of the body, and stor-
ing memory. However, one side usually acts as a
for certain other functions.
Functions of the Cerebral Lobes
Association areas carry on higher intellectual processes
for concentrating, planning, complex problem solving,
and judging the consequences of behavior.
Motor areas control movements of voluntary skeletal
Sensory areas provide sensations of temperature, touch,
pressure, and pain involving the skin.
Association areas function in understanding speech and
in using words to express thoughts and feelings.
Sensory areas are responsible for hearing.
Association areas interpret sensory experiences and
remember visual scenes, music, and other complex
Sensory areas are responsible for vision.
Association areas combine visual images with other
(a) Motor area
(b) Sensory area
Functional regions of the cerebral cortex. (
) Motor areas that control voluntary muscles (only left hemisphere shown). (
areas involved with cutaneous and other senses (only left hemisphere shown).
Tests indicate that the left hemisphere is dominant in 90% of right-
handed adults and in 64% of left-handed ones. The right hemisphere
is dominant in 10% of right-handed adults and in 20% of left-handed
ones. The hemispheres are equally dominant in the remaining 16%
of left-handed persons. As a consequence of hemisphere dominance,
the motor speech area on one side almost completely controls the
motor activities associated with speech. For this reason, over 90% of
patients with language impairment stemming from problems in the
cerebrum have disorders in the left hemisphere.