Department of
Biology

Raghav Rajan studied odour localization in rats for his PhD with Upinder Bhalla at NCBS, Bangalore. For his postdoctoral research, he worked with Allison Doupe at UCSF, San Francisco. There he worked with songbirds on understanding social-context dependent differences in neural activity and song.

Research

Neural mechanisms underlying the initiation and sequencing of natural behaviours

Animals, including humans, produce many complex behaviours consisting of sequences of movements. These behaviours involve the co-ordination of multiple muscles in the body and can be triggered by external and/or internal stimuli. The goal of the Dr. Raghav Rajan's laboratory is two-fold: (1) to understand the neural events that connect the stimulus (internal or external) to the appropriate behavioural response and (2) to understand how the brain controls the order of movements within the behavioural response.

Given their interests in natural, ethologically relevant behaviours, the group uses songbirds as their model system. The song of an adult songbird consists of a sequence of sounds interleaved by silent gaps. Each sound is the result of coordinated activity of vocal (syringeal) and respiratory muscles. Song is part of a courtship ritual triggered by the presence of a female bird. Birds also produce song when they are alone without any external stimulus. Thus song is an excellent example of a complex, natural behaviour (consisting of a sequence of movements) that is triggered by external or internal stimuli.

What are the neural events that lead up to song initiation and what are the neural mechanisms that determine the order of sounds within a song? The Rajan Lab uses a variety of tools, including electrophysiological recordings, pharmacological infusions and behavioural experiments in awake, singing birds to address these questions.

Selected Publications

Kalra S., Yawatkar Y., James L.S., Sakata J.T. and Rajan R. 2021. Introductory gestures before songbird vocal displays are shaped by learning and biological predispositions. Proceedings of the Royal Society: Biological Sciences Jan 27; 288(1943):20202796

Rao D., Kojima S. and Rajan R. 2019. Sensory feedback independent pre-song vocalizations correlate with time to song initiation. Journal of Experimental Biology Apr 9; 222(Pt 7)

Rajan R. 2018. Pre-bout neural activity changes in premotor nucleus HVC correlate with successful initiation of learned song sequence. Journal of Neuroscience Jun 27; 38(26):5925-5938

Woolley S.C., Rajan R., Joshua M. and Doupe A.J. 2014. Emergence of context-dependent variability across a basal ganglia network. Neuron Apr 2; 82: 208-23.

Rajan R. and Doupe A.J. 2013. Behavioral and neural signatures of readiness to initiate a learned motor sequence. Current Biology Jan 7; 23(1):87-93.