Ki Ann Goosens , Ph.D.
Assistant Professor of Neuroscience
Department of Brain and Cognitive Sciences
Neural mechanisms underlying fear and anxiety
Mammals have a highly conserved system for detecting and responding to danger signals in the environment. The fear system integrates information from diverse neural circuits to produce a coordinated, adaptive defensive response. This defensive response derives both from circuits that produce hard-wired, reflexive behaviors, and from circuits that exhibit tremendous plasticity. The defensive response may also be modulated by multiple factors. For example, organisms in a highly aroused or fearful state exhibit activation of neural circuits involved in producing a stress response; the stress response alters defensive behaviors through multiple mechanisms, including increased energy release and activation of the immune system. Thus, a fear state engages multiple parallel circuits which produce a coordinated stereotyped constellation of reflexive behaviors, such as changes in heart rate, activation of the stress axis, and freezing (the cessation of all movement except that necessary for breathing). This behavioral pattern is conserved across mammals, and also is highly similar to those behaviors exhibited in pathological states of fear and anxiety in humans.
Our laboratory uses the fear system to study the mechanisms by which mammalian neurons encode and store information, and to explore the relationship of this code to behavior. We apply techniques such as microarrays and real-time PCR to identify genes that are regulated by conditions that also strongly regulate fear behavior (after chronic stress, for example). We then use a variety of methods, including viral-mediated gene transfer and RNA interference, to probe the contribution of these specific genes to behavioral and electrophysiological measures of fear learning. In addition, we are extremely interested in studying the integration of multiple representations into a coherent and organized behavioral response. To probe the relationship between neural activity in multiple sites, we manipulate activity in one brain region, through either traditional pharmacological techniques or viral-mediated gene transfer, and examine the effects on plasticity or gene expression in additional sites, and behavior. In addition to providing information about the mechanisms by which neurons generally acquire associative memories, our studies also provide insight about neural representations of negative emotion, which may inform treatment of pathophysiological conditions of fear and anxiety in humans, such as post-traumatic stress disorder and panic disorder.