University of Vermont

College of Arts and Sciences

Department of Psychological Science

Sayamwong (Jom) Hammack

Biobehavioral Psychology

Sayamwong (Jom) Hammack

Sayamwong (Jom) Hammack
Associate Professor

  • B.S. Florida State University, 1995
  • M.A. University of Colorado, 1998
  • Ph.D. University of Colorado, 2001
C.V. (PDF)
Phone: (802) 656-1041
Room: 336

Office Hours: Tuesday 8:30-9:30 & Thursday 2:30-3:30 or by appointment

Website: Hammack Laboratory of Behavioral Neuroscience

Director, Undergraduate Neuroscience Program

My research interests involve understanding the neurobiological mechanisms of stress, emotion and resilience. I use a variety of techniques to investigate these mechanisms, which include assessing conditioned and unconditioned fear and anxiety, pharmacological manipulations, neuroanatomical techniques, molecular, and intracellular electrophysiological techniques. I am particularly interested in the involvement of serotonin and stress-related neuropeptides in mediating the behavioral consequences of exposure to stressful stimuli, as well as the neurochemical changes mediating stress-resilience (for example, why does exercise reduce anxiety and make you more resilient in the face of stressors). Specific questions include:

  • What is the role of the bed nucleus of the stria terminalis (BNST) in mediating fear/anxiety behaviors, and how does it accomplish this role?
  • How do brain areas that mediate fear/anxiety behaviors (such as the BNST) respond to serotonin, and is the response to serotonin altered by inescapable stress, chronic stress, or exercise?
  • What are the roles of pituitary adenylate cyclase-activating polypeptide (PACAP) and corticotropin-releasing hormone (CRH) in mediating the behavioral and physiological consequences of stressor exposure?
  • How does exercise alter brain circuits that mediate fear/anxiety behaviors?

Representative Publications

  • Lezak, K.R., Roelke, E., Harris, O., Choi, I., Edwards, S., Gick, N., Cocchiaro, G., Missig, G., Roman, C.W., Braas, K.M., Toufexis, D.J., May, V., Hammack, S.E., (2014) Pituitary adenylyl cyclase activating peptide (PACAP) in the bed nucleus of the stria terminalis (BNST) increases corticosterone in male and female rats, Psychoneuroendocrinology, in press.
  • Lezak, K.R., Roman, C.W., Braas, K.M., Schutz, K.C., Falls, W.A., Schulkin, J., May, V., Hammack, S.E., (2014) Regulation of bed nucleus of the stria terminalis PACAP expression by stress and corticosterone, Journal of Molecular Neuroscience, in press.
  • Kocho-Schellenberg, M., Lezak, K.R., Harris, O.M, Roelke E., Gick, N., Choi, I., Edwards, S., Wasserman, E., Toufexis, D.J., Braas, K.M., May, V., Hammack, S.E., (2014) Pituitary adenylate cyclase activating peptide (PACAP) in the bed nucleus of the stria terminalis (BNST) produces anorexia and weight loss in male and female rats, Neuropsychopharmacology, in press.
  • Hare, B.D., Beierle, J., Toufexis, D.T., Hammack, S.E., Falls, W.A., (2013) Exercise associated changes in the corticosterone response to acute restraint stress: evidence for increased adrenal sensitivity and reduced corticosterone response duration, Neuropsychopharmacology, in press.
  • Hare, B.D., D’Onfro, K.C., Hammack, S.E., Falls, W.A., (2012) Prior stress interferes with the anxiolytic effect of exercise in C57BL/6J mice, Behavioral Neuroscience, 123(6): 850-6.
  • Roman, C.W., Lezak, K.R., Kocho-Schellenberg, M., Garret, M., Braas, K., May, V., Hammack, S.E., (2012). Excitotoxic lesions of the bed nucleus of the stria terminalis (BNST) attenuate the effects of repeated stress on weight gain: Evidence for the recruitment of BNST activity by repeated, but not acute, stress, Behavioural Brain Research, 227(1): 300-4.
  • Hammack, S.E., Cooper, M.A., Lezak, K.R., (2012) Overlapping neurobiology of learned helplessness and conditioned defeat: Implications for PTSD and mood disorders, Neuropharmacology, 62(2):565-75.
  • Ressler, K.J., Mercer, K.B., Bradley, B., Jovanovic, T., Mahan, A., Kerley, K., Norrholm, S.D., Kilaru, V., Smith, A.K., Myers, A.J., Ramirez, M., Engel, A., Hammack., S.E., Toufexis, D., Braas, K.M., Binder, E.B., May, V. (2011) PTSD is associated with the PAC1 receptor and dysregulation of PACAP, Nature, 470: 492-497.
  • Hammack, S.E., Roman, C.W., Lezak, K.R., Kocho-Schellenberg, M., Grimmig, B., Falls, W.A., Braas, K., May, V. (2010) Roles for pituitary adenylate cyclase-activating peptide (PACAP) expression and signaling in the bed nucleus of the stria terminalis (BNST) in mediating the behavioral consequences of chronic stress, Journal of Molecular Neuroscience, 42(3), 327-40.
  • Hammack, S.E., Guo, J., Hazra, R., Dabrowska, J., Myers, K.M., Rainnie, D.G. (2009) The response of neurons in the bed nucleus of the stria terminalis to serotonin: Implications for anxiety, Progress in Neuro-Psychopharmacology & Biological Psychiatry, 33(8): 1309-20.
  • Hammack, S.E., Cheung, J., Rhodes, K.M., Schutz, K.C., Falls, W.A., Braas, K.M., May, V. (2009) Chronic stress increases pituitary adenylate cyclase-activating peptide (PACAP) and brain-derived neurotrophic factor (BDNF) mRNA expression in the bed nucleus of the stria terminalis (BNST): roles for PACAP in anxiety-like behavior, Psychoneuroendocrinology, 34(6), 833-43.
  • Fox, J.H., Hammack, S.E., Falls, W.A. (2008) Exercise is associated with reduction in the anxiogenic effect of mCPP on acoustic startle, Behavioral Neuroscience 122(4), 943-8.
  • Hammack, S.E., Mania, I., Rainnie, D.G. (2007) Differential expression of intrinsic membrane currents in defined cell types of the anterolateral bed nucleus of the stria terminalis, Journal of Neurophysiology 98(2), 638-56.
Acting Chair
Clinical Training Program Director
General/Experimental Program Acting Director
Undergraduate Director
Business Manager
Behavioral Pharmacology
Joint Appointment
Behavior Therapy and Psychotherapy Faculty
Clinical Psychology Internship Program (CPIP)
Post-Doctoral Fellows
Emeriti Faculty
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