Research
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. While simple reflexes, like the knee-jerk reflex, are triggered entirely by external stimuli, more complex behaviours like human speech are triggered by a combination of internal and external stimuli. The goal of our laboratory is to understand the neural events that connect the stimulus (internal or external) to the appropriate behaviour. Given our interests in natural behaviours, we use the zebra finch and other songbirds as our model system.
The song of the male zebra finch, an Australian songbird, consists of a stereotyped sequence of sounds interleaved by silent gaps (Figure on the right - the 'a', 'b', 'c' and 'd' represent the song).
Song is produced by the coordinated activity of vocal (syringeal) and respiratory muscles and is part of a courtship ritual triggered by the presence of a female bird. Male zebra finches also produce song when they are alone without any external stimulus. Thus, zebra finch song is an excellent example of a complex, natural behaviour that is triggered by external stimuli or internal stimuli.
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What are the neural events that lead up to song initiation? By stepping back in time from the onset of the song, the Rajan Lab aims to determine the events leading up to song initiation. We use many different tools, including, electrophysiological recordings, pharmacological infusions and behavioural experiments in awake, singing, birds.
Zebra finches typically begin their song bouts with a variable number of repetitions of a short sound called an introductory note (IN). We aim to determine how INs transition to song and what role they may have in song initiation. In addition, we also investigate changes in neural activity prior to the start of the first IN.
Funding sources (past and current)
IISER Pune, DBT/Wellcome Trust India Alliance, DBT Ramalingaswami Fellowship, SERB, DST CSRI
