Verma, S.; Narayanan, S.; Thirumalai, V.

Synaptic pruning is a dominant process of circuit assembly, known to eliminate a large proportion of synapses formed during development. Yet, very little is understood about how the drastic elimination of a large number of synapses affects circuit computation and behavior. Here, using the olivocerebellar system of larval zebrafish, we first establish the timelines of olivary climbing fiber to Purkinje neuron synaptic pruning. We then show that during this window, encoding of sensory-motor mismatches is improved, sensory representations are fine-tuned, and predictive signals are more robust. All of these lead to faster and better behavioral responses which are adaptable to current sensory input. Thus, developmental synaptic pruning makes circuits fit for complex computations such as predictive processing.