Dr. Srinivas Prasad Kommajosyula of BITS Pilani, Hyderabad Campus, on what optogenetics can and cannot do, and what Indian labs need to use it
Dr. Srinivas Prasad Kommajosyula teaches and researches at BITS Pilani, Hyderabad Campus, which he joined in 2021. He earned his PhD in neuroscience and pharmacology at Southern Illinois University, working on epilepsy, and followed it with postdoctoral research in auditory neuroscience at the Southern Illinois University School of Medicine. His lab uses optogenetics to study how the brain encodes sound. Speaking to NSH after this year’s Nobel Prize for optogenetics, he offered a practitioner’s caution: the technique is a powerful tool, not a cure-all, and Indian labs still depend on imported equipment and vectors.
Before optogenetics, what could neuroscientists not do that they now take for granted? Can you describe an experiment from your own work that would be impossible without it?
Before optogenetics, neuroscientists had to choose between temporal precision and cell-type specificity. Also, the spatial precision of non-optogenetic stimulation methods, such as electrical or pharmacological stimulation, is limited. However, that doesn’t mean optogenetics is the best solution; it has its own pros and cons. Electrical and pharmacological stimulation are widely accepted clinically.
In our lab, we perform several experiments in which we select neurons of a specific genotype to express channelrhodopsin, a light-gated ion channel, depolarise those cells in the auditory cortex with light, and measure the impact on how sound is coded in the cortex or the thalamus.
Popular coverage says optogenetics can “switch on memories” or “map consciousness”. What do such phrases get right, and what do they get wrong?
Optogenetics is a tool for mapping, or dissecting, the system. But switching on memories needs more than activating just one brain region, because memories are encoded in different regions, and retrieving them is not simple; it involves triggering mechanisms. To answer your question in simple terms: it is achievable in theory, but practical difficulties exist with such phrases.
How far is optogenetics from treating patients? What are the main obstacles, and which human application is closest?
Clinical trials for the restoration of vision using optogenetics have been successful and have been published by many groups, and several are under way in hearing research as well. However, applying it to the brain is complicated, owing to fears of an immune response and the difficulty of getting light to penetrate the brain.
What does it take to run optogenetics in an Indian lab today, and what support would help most?
Currently, it is very rare to find a manufacturer in India of optogenetics equipment or of the vectors needed to use optogenetics. This is a gap that scientist-turned-entrepreneurs in India could explore, since most vendors are in the West, in Europe or in China. Another hurdle is the lack of streamlined procedures and the costly process of importing equipment and vectors into India.
