Effects of sensory deprivation and psychedelic drugs on the brain circuits supporting a visuomotor task in zebrafish larvae

Sensory experience is essential for the proper development and function of neural circuits that process and transform sensory information into motor activity. However, the mechanisms by which sensory experience shapes the activity of neural circuits behind visuomotor integrations are not fully understood. In this thesis, I used zebrafish larvae as a model system to study the impact of visual deprivation on the neural circuits that mediate prey capture, a visuomotor task that requires the coordination of eye and tail movements according to the prey position in space. I employed a dark rearing paradigm, to deprive the larvae of the visual input during early stages of development, and assessed its effects on the prey-capture performance. and on the whole-brain neuronal activity patterns of the larvae using volumetric multiphoton calcium imaging. I found significant alterations either in the behaviour and in the neuronal circuit dynamics. Evaluating the recovery capabilities exposing the dark reared larvae to the normal 12h light/12h dark cycle , I found that the circuit plasticity supports only a limited rescue.. Finally, I explored how the psychedelic compound psilocybin, which has been shown to enhance neural plasticity, could reduce the impairments induced by dark rearing. Both prey-capture ability and neuronal circuit dynamics return to normal levels with the drug application. In conclusion, the results revealed the critical role of sensory experience in shaping the neural mechanisms of visuomotor integration and show the capability of psychedelic drugs to recover the visuo- motor task and the salient features of the underlying neuronal network dynamics that were disrupted by dark rearing.