Investigating the Neurophysiological Effects of Direct Current Stimulation (IN6-1.005)

Abstract

Objective: To create a mouse model of direct current stimulation. Background Although transcranial direct current stimulation (tDCS) and deep brain stimulation(DBS) are currently being used as investigative tools in neuroscience and as potential therapies for a variety of neurological conditions, their neurophysiologic mechanisms remain poorly understood. Importantly, no animal studies to date have directly measured physiological changes associated with direct, low-current brain stimulation. Design/Methods: Twenty-four mice were assigned to anodal, cathodal, and sham groups and were implanted with electrodes in left auditory cortex. Mice underwent direct current stimulation for 20min at 20microAmps. Auditory evoked potentials were recorded pre-stimulation, 1hr, 1wk, and 2wk post-stimulation. EEG was analyzed for amplitude/latency of P1, N1, and P2 signals. We assessed EEG power and intertrial coherence using event-related spectral perturbations. Results: In the anodal condition there was significant reduction in delta, theta, and alpha power that persisted through the two-week timepoint. In the cathodal condition there was significant reduction in delta that persisted through the one-week timepoint and reduction in theta and alpha power observed only at the one-hour timepoint (all p values Conclusions: Observed reductions in low frequency power bands after direct current stimulation were consistent with recent clinical studies using tDCS and extracranial EEG recordings (Keeser et al., 2010). In humans, attenuation of low frequency power may be associated with improved cognitive function and increased BOLD signal changes (Hlinka et al., 2010). Our approach may thus provide a means examine the use of direct current stimulation relevant to tDCS and DBS to improve brain function in animal models. Supported by: Summer Research Scholarship, American Academy of Neurology, 2011 and T32 Brain Injury Training Grant, NINDS, 2011. Disclosure: Dr. Rojas has nothing to disclose. Dr. Hamilton has nothing to disclose. Dr. Luminais has nothing to disclose. Dr. Siegel has nothing to disclose.