about
Twitter / X = @vikram0285
Recording and perturbing neural/molecular activity as flies interact with different substrate options and make decisions (e.g., lay eggs) (Vijayan et. al. 2023).
I’m a Postdoctoral Researcher (The Rockefeller University & HHMI) and a Visiting Investigator (Memorial Sloan Kettering Cancer Center) interested in the biological mechanisms that control the timing and outcome of individual behavioral decisions. My work ranges from exploring neural circuits in the brain to investigating subcellular processes within the body. I work with flies — a highly tractable model organism — with the goal of generating insight that also applies to other organisms.
My most recent publications explore the discrete decision to lay an individual egg with the aim of making headway into the neural mechanisms of cognitive decision making. I noticed that flies explore from many seconds to minutes before depositing each egg, and I discovered that flies, remarkably, use a memory of past egg-laying substrate options to assess the relative value of the current option (Vijayan et. al. 2022). I then developed a head-fixed preparation for recording neural activity (two-photon imaging and electrophysiology) as flies explore substrate options and lay eggs, and I discovered a neuronal activity signal in specific neurons that fluctuates up and down – over many seconds to minutes – as a fly explores for an egg-laying site. The fluctuations in this signal likely represent the moment-to-moment “considerations” of the fly. The overall propensity of this signal to rise is related to the relative value of the current option and when this signal hits a threshold level, an egg is deposited (Vijayan et. al. 2023, recorded talk). This rise-to-threshold signal helps extend those previously found in mammals by demonstrating that rising processes can causally initiate action and guide minute-timescale or self-paced deliberations between options (not just seconds-timescale or cued decisions). My work raises the possibility that a similar type of signal may exist in humans choosing a dish at a restaurant, for example.
Holistic and dynamic approach to understanding decisions (fly modified from Kim et. al. 2021).
What next? Flies and mammals share a majority of genes and molecular-level work in flies has led to Nobel prize winning discoveries related to the circadian clock, innate immunity, body development, and more. I plan to leverage the advances from my postdoc (both results and setups) to discover conserved molecular mechanisms for critical neuronal functions. My deep and unique behavioral and neuronal understanding of egg-laying decisions, makes it the perfect system to explore potential conserved and transformative molecular-level mechanisms involved in: (1) homeostasis of neuronal circuits; (2) trans-generational inheritance of environmental information; (3) molecular storage of memory; and more. Of course, to achieve these goals, I am also furthering my understanding at the behavioral and neuronal circuit levels which should also help discover signal and circuit principles for decision-making computations shared with larger brained animals.
While my published work focuses on how real-time signals in the brain guide decision-making behavior, my current/future work expands to even newer territory by also incorporating real-time measurements in the body (e.g., hormone release) during behavior. This direction emerges from my unpublished results (interactions between the brain and endocrine systems regulating the moments of action) and unpublished preparations (a new preparation to measure neural/molecular signals in the body during behavior). By interfacing the genetic tools and connectomes available in flies, with real-time measurements/perturbations in the brain and body during behavior, my lab will have access to the relevant variables to make deep insight into the molecular and circuit mechanisms that support cognitive behavior.
The brain (tiny white structure to left) in comparison to other internal organs (single fly, gray = dapi, cyan = phalloidin).
I’m currently working at The Rockefeller University in the Laboratory of Integrative Brain Function (advisor: Gaby Maimon), with an appointment as a Visiting Investigator at Memorial Sloan Kettering to lead a molecular-level collaboration stemming from my published postdoctoral work (host: Eric Lai). Contact me at vikram.vijayan@gmail.com or on Twitter / X (@vikram0285).
