Drosophila has been used as model organisms to understand the neural basis of sensory behaviour, both innate and learned behaviour. Learning can modulate innate behaviours of animals ensuring flexible and appropriate behavioural responses to changing environmental . We are using larval chemotaxis to understand how innate behaviour is modified by learning and memory.
It has been proposed that a group of neurons in the Drosophila larvae integrates stimuli from innate and learning/memory circuits associated with olfaction. Previous studies have shown the role of group of neurons called Odd neurons in larval innate chemotaxis behaviour. They are situated downstream of the fly olfactory learning and memory centre, the Mushroom Body (MB), and the projection neurons (PNs), which respond directly to odour and as such represent innate sensory input. In this study, we have identified using Trans-Tango method that the Odd neurons receive inputs from the MB neurons depicting their role in learning and memory. We have also identified a role of the Odd neurons in larval odour associated appetitive learning behaviour. Inactivation of Odd neurons inhibit learning and memory in larvae. Temporal inactivation experiments suggests that Odd neurons are required during memory retrieval and not in memory formation suggesting that Odd neurons could integrate olfactory memory with innate olfactory input. We are now investigating how the Odd neurons process both innate and learned stimuli for appropriate behavioural output.
This work would help in understanding the neural mechanisms by which learning and memory modulate different aspects of behaviour.