Biological Bases of Behavior ❮ 83FroNTal loBeS Motor cortex strip just in front of somatosensory cortex initi-
ates movements and integrates activities of skeletal muscles.
Contralateral—right/left hemisphere controls other side
of body.
Broca’s area in left frontal lobe controls production of speech.
Interpret and control emotional behaviors, make decisions,
carry out plans.
TeMPoral loBeS Center for hearing.
Wernicke’s area in left temporal lobe plays role in
understanding language and making meaningful sentences.
Right temporal lobe important for understanding music/tonality.
Sound from both ears processed mostly contralaterally.
Smell processed near front of temporal lobes.Although specific regions of the brain are associated with specific functions, if one
region is damaged, the brain can reorganize to take over its function, which is called plasticity.
In phantom limb syndrome, a somewhat unfortunate example of plasticity, reorganization of
the somatosensory cortex leads to someone experiencing sensations where a missing limb used
to be.structure and Function of the neuron
Your extraordinarily complex brain is composed of trillions of neurons and glial cells. Glial
cells guide the growth of developing neurons, help provide nutrition for and get rid of
wastes of neurons, and form an insulating sheath around neurons that speeds conduction.
The neuron is the basic unit of structure and function of your nervous system. Neurons
perform three major functions: receive information, process it, and transmit it to the rest
of your body. Three major regions of a neuron enable the cell to communicate with other
cells (see Figure 7.3). The cell body (a.k.a. cyton or soma) contains cytoplasm and theMotor
cortex
Somatosensory
cortexBack
of
headBroca’s
area Primary
Visual
Primary cortex
Auditory
cortex
Wernicke’s
areaFront
of
headFRONTAL
LOBE PARIETAL
LOBETEMPORAL
LOBEOCCIPITAL
LOBEFigure 7.2 Regions of the left cerebral cortex in lateral view.