Optogenetics in Neuromodulation: Principles, Neurological Applications, and an Interdisciplinary Correlation with Ayurvedic Medhya Rasayana

Optogenetics is a neuromodulation technique that uses light-sensitive proteins (opsins) to control neuronal activity with millisecond precision and cell-type specificity. Since the seminal work of Boyden et al. (2005) demonstrating Channelrhodopsin-2 (ChR2)-mediated excitation, the field has expanded to include inhibitory opsins like Halorhodopsin (NpHR) and Archaerhodopsin (Arch). This review provides a comprehensive overview of optogenetic principles, viral delivery, light delivery systems, and its applications in Parkinson's disease, epilepsy, depression, and memory engram studies. Additionally, we propose a novel interdisciplinary correlation with Ayurvedic Medhya Rasayana herbs – Brahmi (Bacopa monnieri) and Ashwagandha (Withania somnifera) – known for nootropic, neuroprotective, and adaptogenic properties. We hypothesize that insights from optogenetics could help validate mechanisms of these herbs, and conversely, these herbs could support neuronal resilience in neuromodulation paradigms. Keywords: Optogenetics, ChR2, NpHR, Neuromodulation, Parkinson's, Epilepsy, Memory Engram, Bacopa monnieri, Withania somnifera, Medhya Rasayana