Abstract
Purpose :
Transcranial direct current stimulation (tDCS) has been attracting attention as a non-invasive neuromodulation method. The purpose of this study is to investigate whether tDCS enhances the performance of retinal prosthses.
Methods :
Nine Long-Evans rats were anesthetized with urethane (1.75g/kg). Right visual cortex was exposed by craniotomy, and 2mm-diameter electrode for tDCS was placed on the skull adjacent to the exposed area. Anodal direct current (0.1 mA, 10 minutes) was applied to the electrode. Visually evoked potentials (VEPs) and electrically evoked potentials (EEPs) were recorded before and after the application of tDCS. For EEP measurement, electrical stimulation was suprachoroidally applied to the left eye of rats.
Results :
Significant increase of VEP amplitude was observed after tDCS (p<0.05, paired t-test). The increase of VEP was maintained almost for three hours. Averaged VEP amplitude (normalized by the VEP amplitude before tDCS) was 1.6 at 5 minutes after tDCS, 2.1 at 30 minutes after tDCS, and 3.0 at 150 minutes after tDCS. On the other hand, no statistically significant increase of EEP amplitude was observed after tDCS.
Conclusions :
Results indicated that neural excitability could be modulated by tDCS. Results also suggested that tDCS used in this study was ineffective for the enhancement of EEP amplitude. We will explore parameters on the transcranal stimulation as the next step.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.