Sherif Elbasiouny (Committee Member), Ryan Jankord (Committee Co-Chair), Larry Ream (Committee Co-Chair)
Master of Science (MS)
Transcranial Direct Current Stimulation (tDCS) has been used to treat various mental and neurological illnesses. Rodent models have been used to examine physiological changes in the brain after tDCS, as well as to develop safety standards. However, most animal tDCS studies implant an electrode on the brain, potentially altering the path of current during stimulation. Additionally, no studies have been completed specifically examining maximum safe anodal tDCS limits, and a pilot study conducted to determine an electrode montage to examine biological changes of learning and memory from anodal tDCS indicated brain lesion was occurring before a commonly cited lesion threshold of 142.9 A/m2. Therefore, the goal of this study was to examine both the effects of anodal tDCS and the rodent's scalp on current shunting during anodal tDCS in vivo. Anodal tDCS was applied to the skull of 35 anesthetized male Sprague-Dawley rats for 60 minutes after they were divided into groups either receiving stimulation with an electrode on the skull or scalp tissue. Within each skull and scalp electrode placement group, rats were further separated into groups by tDCS current intensity (µA) received, which was: sham (n=4), 150 µA (n=4), 300 µA (n=4), 500 µA (n=3), 1,000 µA (n=4), and 2,500 µA (n=3) for the skull electrode placement group. For the scalp electrode placement groups, only stimulations that induced lesion during the skull electrode stimulation were chosen: sham iv Distribution A: Approved for public release; distribution unlimited. 88ABW Cleared 11/09/2015; 88ABW-2015-5473. (n=2), 500 µA (n=3), 1,000 µA (n=3), and 2,500 µA (n=3). Brain lesion was quantified using an Olympus BX-63 microscope with Q100 Blue Camera and CellSens software, which showed brain lesion during skull electrode placement first occurring at 500 uA, having a lesion volume of 0.168 mm3. At 1,000 µA and 2,500 µA, the average brain lesion within groups was 6.363 mm3 and 13.013 mm3, respectively. Stimulation of the scalp showed no brain lesion at any of the stimulation groups, suggesting the scalp tissue shunts a portion of the current, and as a result, has different physiological effects on brain lesion development.
Department or Program
Department of Neuroscience, Cell Biology, and Physiology
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