Behavioral Neurology Unit
Dr. Wassermann received his B.A. from Swarthmore College, his M.A. from the University of Pennsylvania, and his M.D. from New York Medical College. After neurology residency at the Boston City Hospital, he came to the NINDS Human Motor Control Section as a postdoc, to study motor cortex physiology and the control of voluntary movement.
Dr. Wassermann has received the the Pfizer Visiting Professorship in psychiatry, two NIH Director's Awards, and the US Public Health Service Outstanding Service Medal. He serves on the leadership of the Center for Neuroscience and Regenerative Medicine and is a leading expert on transcranial brain stimulation and neuromodulation techniques.
In 2004-2007, he was detailed to the Office of the Assistant Secretary for Preparedness and Response, DHHS as an expert in chemical casualty care and response planning.
We study the brain systems underlying learning, executive function, and behavioral regulation, using noninvasive brain stimulation, functional and structural neuroimaging, and innovative behavioral tools. The main thrust of our basic human research is how to make learning and memory more efficient, particularly in ways that avoid the risks and regulatory burdens of drugs and neuromodulatory devices. Current projects in this area include a behavioral and functional MRI study of how adding reward improves procedural learning and counteracts the temporary negative effects of inhibitory transcranial magnetic stimulation delivered to the motor and prefrontal cortex. We are also studying the effect of brief, intense, exercise on memory for recently learned material.
Our main clinical interest is in the physiological and neuroanatomical basis of excess fatigue and mental slowness after brain injury. In particular, we are investigating the role of dopaminergic structures and pathways in these clinically important problems. Ongoing clinical studies include the evaluation of warfighters with symptomatic traumatic brain injury and military and civilian professionals whose occupations expose regularly to explosive blast. We are also collaborating on a clinical trial of methylphenidate in patients with residual cognitive deficits after traumatic brain injury, testing raclopride PET scanning, functional MRI, and transcranial magnetic stimulation as predictors of clinical response. Some of our work is sponsored by the Center for Neuroscience and Regenerative Medicine at the Uniformed Services University of the Health Sciences (USUHS).
Transcranial Brain Stimulation
We have been involved used transcranial brain stimulation as a research tool since 1989 and have performed some of the key studies to validate the techniques and establish guidelines for their safe use. Transcranial magnetic stimulation is a noninvasive means of getting electrical energy across the insulating tissues of the head and into the brain. A powerful and rapidly changing electrical current is passed through a coil of wire applied near the head. The magnetic field, oriented perpendicular to the plane of the coil passes virtually unimpeded through the scalp and skull. In the brain, the magnetic field produces currents in the induced electrical field lying parallel to the plane of the coil. These currents are able to excite neural processes lying in the plane of the induced field in a manner roughly analogous to direct cortical stimulation with electrodes. In properly designed experiments, TMS can be a powerful physiological probe of cortical cortical function for clinical and basic neurophysiology. It is also an effective technique for altering the responsiveness of human brain circuits and may have therapeutic applications, as well. DC brain polarization is a decades old technique for modulating the activity of neural tissues. These effects are selective for the polarity and the orientation of neurons in the field. The older literature contains instances of its ability to produce overt changes in behavior and newer studies show that quantifiable alterations in human behavioral and physiological responses can be produced safely, although the reproducibility of some of these effects is in question. One of our aims is to promote robust research in this area and facilitate the transfer of transcranial stimulation techniques from the laboratory to the clinic.
The Effect of Transcranial Magnetic Stimulation on Learning With Reward in Healthy Humans 11-N-0055
Fatigue and Amotivation Following Mild Traumatic Brain Injury and their Influence on Service Member Community Reintegration 12-N-0030
Experienced Breacher Study: Evaluation of the Effects from Chronic Exposure to Low-Level Blast 12-N-0065
Sildenafil for Cerebrovascular Dysfunction in Chronic Traumatic Brain Injury 13-N-0008
Acute effects of exercise on memory in healthy and brain-injured individuals 13-N-0198
Dopamine Receptor Imaging to Predict Response to Stimulant Therapy in Chronic TBI 14-N-0196
Effect of administration of recombinant erythropoietin on numbers of circulating endothelial progenitor cells in patients with persistent symptoms during the subacute period after Traumatic Brain Injury 14-N-0174
Kristine Dell, B.A.
Kris Knutson, M.S.
Philip Koshy, B.A.
Post baccalaureate Fellow
Jeffrey Lewis, M.D., Ph.D.
Selene Schintu, Ph.D.
Michael Tierney, M.A.
Leonora Wilkinson, Ph.D.