Jeff,
Below are two excerpts from tutorials to accompany undergraduate course work
in biopsych (intro and slightly more advanced). References available upon
request.
First excerpt -
The Amygdala is a structure included in the Limbic System (hyperlink to Fig
8) of the forebrain. Like other structures within this functional system,
the amygdala is involved in the control of emotion (particularly aggression),
and perhaps plays a supportive role in the formation of memories.
Advanced:
Electrical stimulation of the amygdala can lead to extremely aggressive
behavior, whereas damage usually results in tame and docile behavior even in
the face of provocation. In addition to modulating emotional responses, the
amygdala contributes to the interpretation of sensory information. Animals
with amygdala damage may sexually mount inappropriate partners including
inanimate objects and members of other species. Monkeys with amygdala damage
may misinterpret social information leading to inappropriate attacks on other
monkeys or failure to attack when truly under threat.
Second excerpt -
The Amygdala, meaning almond-shaped, is located within the temporal lobe near
the front or anterior boundary, and is an important component of the Limbic
System. This structure plays a specific role in the memory of experiences
having emotional significance.
Advanced:
The amygdala receives information from the olfactory system (hyperlink to
fig. 18), temporal cortex (hyperlink to fig 9), thalamus, midbrain (hyperlink
to Fig. 6), and hypothalamus. In addition, this structure responds to a
variety of stimuli. In general, the amygdala appears to specialize in
modulating reactions to objects and events of special biological
significance; those that warn of pain or danger, or signify the presence of
food or water, potential mates or rivals, or infants in need of support. The
amygdala, in relation with other regions of the cerebrum, provides the
substrate for modulating aggressive, defensive, reproductive and maternal
behavior. Indeed, as mentioned in Figure 7 (hyperlink to 7), destruction of
different regions of the amygdala will typically result in the inhibition of
defensive behavior and the alteration of reproductive behavior. The
corticomedial amygdala appears to inhibit predatory behavior, in particular
against a former and more dominant opponent. This mechanism has important
ramifications for self-preservation. The basolateral amygdala appears to
stimulate defensive attack. The amygdala is also involved in mediating the
effects of pheromones (hyperlink to Figure 18) on reproductive physiology and
behavior (hyperlink to Figure 12), in the control of salt intake, and in the
learning of taste aversions and other classically-conditioned emotional
responses. Research indicates that prescription, anti-anxiety medication may
suppress activity within the amygdala.
Sandra Nagel Randall
in Michigan and elsewhere
<A HREF="http://members.aol.com/snrandall">Sandra Nagel Randall - CV</A>
