7/21/2019 intervention in the brain
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4 Chapter 1
is remarkable. Although it is only about 2 millimeters thick,
its surface
area is about 1.5 square meters and contains some ten to fifteen
billion
neurons, four times as many glial cells, and an estimated one
million
billion synaptic connections.
Roughly divided into the occipital, temporal, parietal, and
frontal
lobes on each side, the cerebral cortex contains numerous
sensory receiv-
ing, motor control, language, and associated areas, with many
regions
having multiple functions. The frontal lobes, for instance, are
thought
to be the center of the higher-order processes that give us the
capacity to
engage in abstract thinking, planning, and problem solving.
Moreover,
located at the base of the temporal lobe, the hippocampus is
critical to
learning and for the consolidation of recently acquired
information, orshort-term memory. Closely situated at the base of
the frontal lobes are
the basal ganglia nuclei, which are associated with a variety of
functions,
including voluntary motor control, procedural learning of
routine behav-
iors, and action selection, that is, the determination of which
of several
possible behaviors to execute at a given time.
The human frontal lobes constitute almost 40 percent of the
total
cortical area and, as the last cortical areas to mature, are
connected to
almost every other part of the brain, including the behaviorally
criticallimbic system. These extensive connections form the basis
for the impor-
tance of the frontal lobe as an integrator and regulator of
brain func-
tion (Restak 1994, 96). Extensive experience with patients who
have
suffered frontal lobe dysfunction demonstrates how critical they
are to
human thought and behavior. Humans are the only species capable
of
anticipating the future consequences of present actions, setting
up plans
and goals and working toward their achievement, balancing and
control-
ling the emotions, and maintaining a sense of ourselves as
active con-tributors to our future well-being. All these powers are
diminished with
frontal lobe disease.
The upper brain is surrounded by the cerebral cortex and
contains
discrete structures, including the hypothalamus and the
thalamus. Each
of these structures is composed of a collection of nuclei with
specific
functions. The thalamic nuclei are primarily involved in
analyzing and
relaying all the sensory and motor information coming into the
brain.
Similarly, neurons in the hypothalamus serve as relay stations
for internal
regulatory systems by monitoring information arriving from the
auto-
nomic nervous system and controlling behaviors such as eating,
drinking,
and sexual activity. This dime-sized region of the brain,
comprised of ten
or so nuclei on each side, controls and modulates sexual
behavior, regu-
