While the physiological and behavioral responses to an imminent threat that comprise the `fight-or-flight’ phenomenon are regulated by subcortical neural networks centered on the amygdala, LeDoux and Pine propose that the subjective experience of fear is regulated by higher order cortical networks responsible for cognitive processes such as attention and working memory.
This new model would replace the long-accepted “fear circuit” model, in which both physiological reactions and the subjective experience of fear are regulated by one circuit centered on the amygdala. LeDoux and Pine make the same distinction for anxiety and other emotions—different circuits underlie the conscious feelings of these emotions and those that underlie the behavioral and physiological responses that occur in tandem.
If LeDoux and Pine are correct it suggests that animal models used to test medications for treating anxiety disorders—founded on the more traditional unitary fear circuit theory—may not adequately capture the subjective experience of fear and anxiety as felt by humans.
“This is a really important paper,” Murray Stein, M.D., vice chair for clinical research in the Department of Psychiatry at the University of California, San Diego, told Psychiatric News. “[L]eDoux and Pine suggest we have been going down the wrong path ... because what we are modeling in animals isn’t what we are measuring, assessing, and trying to treat in humans.”
“Animal research is important and useful, especially if we know how to use it,” LeDoux said. “Our ability to understand the brain is only as good is our understanding of the psychological processes involved. If we have misunderstood what fear and anxiety are, it is not surprising that efforts to use research based on this misunderstanding to treat problems with fear and anxiety would have produced disappointing results.”
For related information, see the Psychiatric News article “Humans, Rodents Pay Close Attention to Fear, Anxiety Expressed by Parents.”