The Neural Circuits that Underlie Fear

This chapter reports the data derived from electrocortical and neuroimaging studies which provide strong evidence for a possible neuroanatomical circuit underlying fear responses and shyness in humans. It starts with a selective overview of the some of the key circuitry that underlies two major emotional and motivational systems - the approach and withdrawal systems. It also addresses individual differences in these basic systems, indicates how such differences might be studied, and discusses the behavioral consequences of such individual differences. In addition, it specifically considers the problem of behavioral inhibition and offers new findings on relations between prefrontal asymmetry and measures of behavioral inhibition in a longitudinal sample. Lastly, it evaluates some of the implications of these data for understanding the mechanisms that underlie behavioral inhibition. It is shown that neither the measures of brain function nor the behavioral measures of inhibition are stable from age 3 to 10 years even though measures of prefrontal activation asymmetry predict concurrent measures of behavioral inhibition.