Sensorimotor integration in visuomotor tasks: trajectory analysis in occipitoparietal lesions and action-dependent effects on perception in virtual reality

Sensorimotor integration is a fundamental process that underlies our ability to interact with and perceive the world around us. The integration of sensory information with motor actions enables precise movement execution and plays a crucial role in shaping our perception. Neurological conditions caused by parietal lesions can disrupt this intricate process, leading to impairments in movement execution and control. In the first study of this thesis, we evaluated how visuomotor disruption caused by an occipitoparietal lesion in a patient with optic ataxia symptoms impairs motor trajectories during visually guided reaching movements. To this end, we compared the trajectories performed by the patient with those performed by a healthy control group by using a novel decoding approach. We found that the trajectories of the two groups were highly distinguishable already before the midpoint of the movement, suggesting the potential of this decoding method to characterize pathological motor behaviours. In the second study of this thesis, we investigated sensorimotor integration using another novel approach: virtual reality. In fact, previous research indicates that the perception of space and objects in virtual environments is usually inaccurate but can be improved by interacting with the environment through walking, though not by reaching. To evaluate this, we used a size-judgment task to assess how different interactions, such as simulated walking, reaching and grasping, affect object perception in virtual reality. Contrary to our expectations, which were based on real-world studies showing that grasping enhances size perception, we found that mere observation was the most beneficial interaction for performing the task. The exploration of the effects of neurological impairments on movement trajectories and the influence of various actions on perception in virtual reality offers significant implications for clinical rehabilitation and our understanding of sensorimotor processing.