Fears can be acquired extremely rapidly and once acquired, can last a lifetime. I use Pavlovian conditioning paradigms to produce fearful memories in rats. To test for the presence and strength of those memories, I measure the startle reflex, the size of which is elevated when a rat (or other mammal, including human) is afraid.
"Fear-potentiated startle" provides us with a tool to identify brain structures, and to study pharmacological and molecular mechanisms involved in different aspects of the formation and retrieval of fearful memories. Furthermore, the startle response is chronically elevated in certain forms of anxiety disorder and during withdrawal from certain drugs of abuse. Thus, understanding the mechanisms through which startle can be elevated provides insights into the pathophysiology and treatment of anxiety and drug addiction.
Burman, M.A., & Gewirtz, J.C. (2007). Hippocampal activity, but not plasticity, is required for early consolidation of fear conditioning with a short trace interval. European Journal of Neuroscience, 25, 2483-2490.
Harris, A.C., Atkinson, D.B., Aase, D.M., & Gewirtz, J.C. (2006). Double dissociation in the neural substrates of acute opiate dependence as measured by withdrawal-potentiated startle. Neuroscience, 139, 1201-1210.
Hamilton, K.L., Harris, A.C., Gewirtz, J.C., Sparber, S.B., & Schrott, L.M. (2005). HPA axis dysregulation following prenatal opiate exposure and postnatal withdrawal. Neurotoxicology & Teratology, 27, 95-103.
Josselyn, S.A., Falls, W.A., Gewirtz, J.C., Pistell, P., & Davis, M. (2005). The nucleus accumbens is not critically involved in mediating the effects of a safety signal on behavior. Neuropsychopharmacology, 30, 17-26.
Burman, M.A., & Gewirtz, J.C. (2004). Timing of fear expression in trace and delay conditioning measured by fear-potentiated startle in rats. Learning and Memory, 11, 205-212.
Harris, A.C., & Gewirtz, J.C. (2004). Elevated startle during withdrawal from acute morphine: A model of opiate withdrawal and anxiety. Psychopharmacology, 171, 140-147.
