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proprioceptive feedback from facial muscles constitutes the
experience of emotion. According to Tomkins, emotion-
specific innate programs for groups of facial expressions
are stored in subcortical centers. Tomkins hypothesized
that once an emotion has been activated, facial feedback is
provided to the cortex. Additionally, Tomkins argued that
it is the facial feedback that initiates visceral
activation.
Differing slightly from Tomkins, Izard (1977) argued
that emotion involves three components; neural activity or
the density of neural firing per unit time, striate muscle
feedback to the brain, and subjective experience. Izard
posited that each component can be dissociated from the
others, but that the three are normally interdependent.
Specifically, according to Izard, internal or external
stimuli affect the gradient of neural stimulation in the
limbic system and sensory cortex. Information from these
areas are relayed to the hypothalamus which plays a role in
determining the facial expression to be effected. From the
hypothalamus, impulses are relayed to the basal ganglia
where the neural message for facial expression is mediated
by motor cortex. Impulses from motor cortex, via cranial
nerve VII lead to the specific facial expression. Cranial
nerve V receives sensory input from the face and projects,
via the posterior hypothalamus, to sensory cortex. It is