Demetrio Sierra


Dr. Demetrio Sierra came to the UPR Medical Sciences Campus from the Massachusetts General Hospital / Harvard University in 2014. As a graduate student at Ponce School of Medicine, he explored the biological markers of emotional regulation using a rodent model of Pavlovian fear conditioning and extinction. He demonstrated that fear regulation requires an interaction between the prefrontal cortex, hippocampus, and amygdala. As a postdoc at Harvard, Sierra extended his training to the non-human primate (NHP) in a study of avoidance and reward seeking. He also extended his graduate work on fear and extinction learning to a rodent model of Traumatic Brain Injury, which is thought to be a risk factor for development of anxiety disorders. He is therefore exceptionally well prepared to undertake the current study that examines relationships between TBI and PTSD.


  • Postdoc, Neuropharmacology and Neurophysiology, Columbia University, New York, NY
  • Ph.D., Biochemistry, University of Puerto Rico, Río Piedras Campus, San Juan, P.R.
  • B.S., Chemistry, University of Puerto Rico, Río Piedras Campus, San Juan, P.R.

Research Interests

  • Neuronal Nicotinic Acetylcholine Receptor
  • Monoamine Transporters and Receptors
  • Amphetamine-type Psychostimulants
  • Parkinson Disease and L-DOPA-induced Dyskinesia
  • Electrophysiology and Electrochemistry
  • Confocal and Two-photon Microscopy
  • Time-correlated Single Photon Counting
  • Molecular & Cell Biology
  • Behavioral Paradigms