Abstract: Hippocampal Theta Rhythm Stimulation Restores Cognitive Ability In Rodents Following Traumatic Brain Injury (2011 SACNAS National Conference)

Saturday, October 29, 2011

Hall 1-2 (San Jose Convention Center)

Hiram M. Dominguez , Department of Psychological & Brain Sciences, University of California, Santa Barbara, Santa Barbara, CA

Darrin J. Lee, MD , Department of Neurological Surgery, University of California, Davis, Davis, CA

Gene G. Gurkoff, PhD , Department of Neurological Surgery, University of California, Davis, Davis, CA

Ali Izadi, BS , Department of Neurological Surgery, University of California, Davis, Davis, CA

Philip A. Schwartzkroin, PhD , Department of Neurological Surgery, University of California, Davis, Davis, CA

Robert F. Berman, PhD , Department of Neurological Surgery, University of California, Davis, Davis, CA

J. Paul Muizelaar, MD, PhD , Department of Neurological Surgery, University of California, Davis, Davis, CA

Kiarash Shahlaie, MD, PhD , Department of Neurological Surgery, University of California, Davis, Davis, CA

Bruce G. Lyeth, PhD , Department of Neurological Surgery, University of California, Davis, Davis, CA

Over 1.7 million cases of traumatic brain injury (TBI) are reported each year in the United States alone. A major consequence of TBI is a deficit in learning and memory. To date there is no effective treatment to restore cognitive function. The hippocampus is known to be associated with learning and memory. More specifically, the hippocampal theta electroencephalographic (EEG) frequency is believed to be involved in working memory. Our lab previously found attenuation of hippocampal theta and deficits in hippocampal-dependent memory tasks in rats following TBI when compared to sham. The medial septal area (MSA) is a region of the brain that provides cholinergic input to the hippocampus and drives theta activity. The goal of the current study was to determine if electrical theta stimulation in the MSA improves learning and memory. Sprague-Dawley rats received either lateral fluid percussion (LFP) TBI or sham injury. Following injury, a stimulating MSA electrode and recording hippocampal electrode were implanted. Experimental groups included the following: sham+no stimulation, sham+stimulation, TBI+no stimulation, and TBI+stimulation. Working memory was assessed using the Barnes maze, a spatial learning task. Continuous stimulation in the theta frequency (7.7 Hz) occurred during the behavioral task. Daily EEG data was collected. Our results demonstrate an improvement in spatial working memory in the TBI+stim group relative to TBI+no stim. These exciting results suggest that stimulation improves outcome in rats following TBI. Our goal is to translate theta rhythm stimulation into treatment for TBI patients with memory deficits.