Analyzing the Impact of Transcranial Direct Current Stimulation on the Human Primary Visual Cortex through fMRI-based Brain Entropy

Motivation: Specific impact of Transcranial Direct Current Stimulation (tDCS) on the human primary visual cortex (V1) remains unclear. Goal(s): We used fMRI-based brain entropy (BEN) method to investigate the effects of short- and long-term tDCS on brain activity, and dynamic changes of BEN during tDCS. Approach: The resting-state fMRl data were collected before, during and after stimulation from 10 healthy subjects. Results: We observed reduced BEN values after both short- and long-term tDCS in frontoparietal and occipital areas. During tDCS, the brain preferred to stay in a state with lower BEN values in the default mode network compared to other brain regions. Impact: Short- and long-term tDCS on V1 both have a positive effect on improving cognitive functions in healthy and psychiatric disorder population. We also further validated the utility of BEN as an effective method for assessing tDCS effects.