Aside from control of our limbs which involve direct feedback of
mechanical variables through the spinal cord, the control of physiological
states of the body by the limbic system are well known and are described
in most introductory neuroscience textbooks. A particularly good
discussion is in Kandel et al., Principles of Neuroscience, (3rd Ed.) Ch.
47 & 48. The hypothalamus is known to control internal temperature, degree
of hydration and other physiological parameters by direct action and
through the autonomic nervous system. Figure 48-1 in Kandel shows a
general control circuit for this in terms of the standard analog feedback
control concepts of error signal, controlled system and feedback.
In addition to controlling simple variables such as sodium ion
concentration in the tissues through regulation of water retention by the
kidneys, higher order behaviors are elicited by these systems. If external
temperature becomes too cold behaviors to seek shelter are elicited which
result in increased internal temperature.
An interesting aspect of the limbic control system is the hierarchical
relationship between the amygdala and the hypothalamus. The hypothalamus
regulates simple variables such as temperature. The amygdala, which is
typically associated with fear and anxiety reactions, is part of the
limbic control system but receives predominantly higher order sensory
inputs and thus perceives more complex inputs and reacts by sending
signals to lower control areas in the hypothalamus and other areas to
effect the physiological state of the body. A good discussion of this is
given in Aggelton, Ed., The Amygdala: Neurobiological aspects of emotion.
memory and mental dysfunction, Ch 9, especially Fig. 13.
Jack
---------------------------
Jack Gelfand
Princeton University
Department of Psychology
Princeton, NJ 08544
http://www.princeton.edu/~jjg