- Biological processes underlying learning and memory
- Producing animal models of human psychopathology
- Neural substrates of fear conditioning
My work concerns the biological substrates of memory, fear, and anxiety, and drug dependence. 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. Moreover, dramatic elevations in startle accompany certain forms of anxiety disorder and the anxiety-related symptoms of drug withdrawal. Thus, understanding the mechanisms through which startle is potentiated provides insights into the pathophysiology and treatment of anxiety and drug abuse.
(For a comprehensive list of recent publications, refer to PubMed, a service provided by the National Library of Medicine.)
Engelmann JM, Versace F, Gewirtz JC, Cinciripini PM. Individual differences in brain responses to cigarette-related cues and pleasant stimuli in young smokers. Drug Alcohol Depend. 2016 Apr 25;. [Epub ahead of print]
Radke AK, Gewirtz JC, Carroll ME. Effects of age, but not sex, on elevated startle during withdrawal from acute morphine in adolescent and adult rats. Behav Pharmacol. 2015 Aug;26(5):485-8.
Kennedy, B. C., Dimova, J. G., Siddappa, A. J., Tran, P. V., Gewirtz, J. C., & Georgieff, M. K. Prenatal Choline Supplementation Ameliorates the Long-Term Neurobehavioral Effects of Fetal-Neonatal Iron Deficiency in Rats. The Journal of nutrition, 2014 Nov;144(11), 1858-1865.
Hamilton KL, Harris AC, Gewirtz JC. Affective and neuroendocrine effects of withdrawal from chronic, long-acting opiate administration. Brain Res. 2013 Nov 13;1538:73-82.
Pisansky MT, Wickham RJ, Su J, Fretham S, Yuan LL, Sun M, Gewirtz JC, Georgieff MK. Iron deficiency with or without anemia impairs prepulse inhibition of the startle reflex. Hippocampus. 2013 Oct;23(10):952-62.
Blegen MB, Kennedy BC, Thibert KA, Gewirtz JC, Tran PV, Georgieff MK. Multigenerational effects of fetal-neonatal iron deficiency on hippocampal BDNF signaling. Physiol Rep. 2013 Oct;1(5):e00096.
Radke AK, Holtz NA, Gewirtz JC, Carroll ME. Reduced emotional signs of opiate withdrawal in rats selectively bred for low (LoS) versus high (HiS) saccharin intake. Psychopharmacology (Berl). 2013 May;227(1):117-26.
Rothwell PE, Thomas MJ, Gewirtz JC. Protracted manifestations of acute dependence after a single morphine exposure. Psychopharmacology (Berl). 2011 Aug 11.
Radke AK, Rothwell PE, Gewirtz JC. An anatomical basis for opponent process mechanisms of opiate withdrawal. J Neurosci. 2011 May 18;31(20):7533-9.
Burman, M.A., Hamilton, K.L., & Gewirtz, J.C. (2010). Role of corticosterone in trace and delay conditioned fear-potentiated startle in Rats. Behavioral Neuroscience, 124, 294-299.
Sun, M., Gewirtz, J.C., Bofenkamp, L., Wickham, R.J., Ge, H., O’Connor, M.B. (2010). Canonical TGF-beta signaling is required for the balance of excitatory/inhibitory transmission within the hippocampus and prepulse inhibition of acoustic startle. Journal of Neuroscience, 30, 6025-6035.
Engelmann, J.M., Radke, A.K., & Gewirtz, J.C. (2009). Potentiated startle as a measure of the negative affective consequences of repeated exposure to nicotine in rats. Psychopharmacology. 2009 Nov;207(1):13-25.
Rothwell, P.E., Thomas, M.J., & Gewirtz, J.C. (2009). Distinct profiles of anxiety and dysphoria during spontaneous withdrawal from acute morphine exposure. Neuropsychopharmacology. 2009 Sep;34(10):2285-95.
Gewirtz, J.C., Hamilton, K.L., Babu, M.A., Wobken, J.D., Georgieff, M.K. (2008). Effects of gestational iron deficiency on fear conditioning in juvenile and adult rats. Brain Research, 1237, 195-203.
Raman, L., Hamilton, K.L., Gewirtz, J.C., & Rao, R. (2008). Effects of chronic hypoxia in developing rats on dendritic morphology the CA1 subarea of the hippocampus and on fear-potentiated startle. Brain Research, 1190, 167-174.
Harris, A.C., Rothwell, P.E., & Gewirtz, J.C. (2008). Effects of the NMDA receptor antagonist memantine on the expression and development of acute opiate dependence as assessed by withdrawal-potentiated startle and hyperalgesia. Psychopharmacology, 196, 649-660.
Former Graduate Students:
Marc Pisansky (Ph.D. 2016, Neuroscience, University of Minnesota).
Bruce Kennedy (Ph.D. 2016, Neuroscience, University of Minnesota).
Anna Radke (Ph.D. 2011, Neuroscience, University of Minnesota).