Who Needs Emotions? The Brain Meets the Robot

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The medial prefrontal cortex may thus serve as an interface between
cognitive and emotional systems, allowing cognitive information processing
in the prefrontal cortex to regulate emotional processing by the amygdala.
In addition, emotional processing by the amygdala may influence decision
making and other cognitive functions of the prefrontal cortex. Consequently,
prefrontal–amygdala interactions may be involved in the conscious feelings
of fear (see section below).
In humans, damage to the amygdala interferes with implicit emotional
memories but not explicit memories about emotions, whereas damage to
the medial temporal lobe memory system interferes with explicit memories
about emotions but not with implicit emotional memories (Bechara,
Damasio, & Damasio, 2003; LaBar, Crupain, Voyvodic, & McCarthy, 2003).
While explicit memories with and without emotional content are formed
by way of the medial temporal lobe, those with emotional content differ from
those without such content. The former tend to be longer-lasting and more
vivid (Christianson, 1992; Cahill & McGaugh, 1998). Lesions of the amygdala
or systemic administration of a b-adrenergic antagonist prevent this amplifying
effect of emotion on declarative memory (Cahill & McGaugh, 1998),
suggesting that the amygdala can modulate the storage of explicit memories
in cortical areas. At the same time, the medial temporal lobe memory system
projects to the amygdala (see above). Retrieval of long-term memories
of traumatic events may trigger fear reactions by way of these projections to
the amygdala.
WHAT ABOUT FEELINGS?
Consciousness
Our discussion above of the relation between the study of emotion in rats
and humans brings us at last to the issue of how the conscious dimension of
“feelings” in humans relates to the processing approach that has proved so
successful in the study of rats. Subjective emotional experience, like the
feeling of being afraid, results when we become consciously aware that an
emotion system of the brain, like the defense system, is active. In order for
this to occur, we need at least two things: a defense system and the capacity
to be consciously aware of its activity. The up side of this line of thought is
that once we understand consciousness, we will also understand subjective
emotional experiences. Many believe that the down side is that in order to
understand subjective emotional experiences, we need to understand consciousness.
However, it might be argued that our “divide-and-conquer” ap-