Thesis defense Alireza Azarfar (Donders series 353)

6 December 2018

Promotor: prof. dr. T. Celikel, co-promotor: dr. F. Zeldenrust

Adaptive sensorimotor control for navigation

During the sensorimotor computation, motor behavior adapts to context and task requirements as sensory information modulates the motor command to enable adaptive sensing, and presumably to optimize the behavioral performance. This thesis addressed 1) the emergence of adaptive sensorimotor control during postnatal development, 2) the influence of neuromodulatory mechanisms on this development, 3) sensory consequences of adaptive sensorimotor control, and 4) integration of feedforward motor predictions with sensory feedback in this computation. The results showed that adaptive sensorimotor control strategies in rats performing an object localization task mature later in life, although juvenile rats are capable of successful object localization. The results further indicated that sustained alterations of serotonergic signaling impair the emergence of sensorimotor adaptation in adulthood. Therefore I propose that postnatal development of adaptive motor control requires intact serotonergic signaling and that even transient alterations in serotonergic signaling early during development cause long-term sensorimotor disturbances in the adulthood. One of the sensory consequences of adaptive motor control is the increased signal to noise ratio in neural representations while reducing the processing load in sensory organs. To bring these observations together, I propose a Bayesian filtering framework and argue that adaptive whisking increases certainty in object localization task by reducing the sensory and process noise.