Feb. 17, 11:45, Wei Ji Ma. Optimality and Probabilistic Computation in Visual Categorization


Elizabeth Torres, Rutgers University

Intended and automated modes of action co-exist during both real and imagined acts and can be used to define different forms of cognitive control

Activities of daily living can be of different kinds. Among instrumental acts are those in the reaching family. They typically involve the coordination of one of the upper extremities with the head and trunk to achieve a goal. These instrumental acts require directing our attention towards well defined targets –at least during some portions of the action.  We typically call these motions intended acts. The field of motor control studies primarily these types of acts. Less explored are more complex acts that involve the simultaneous control of all limbs, head and trunk, typically guided by multiple goals. Examples include body gestures paired with speech production, general daily activities (e.g. preparing a cup of tea, driving a car, etc.), sports, dancing, playing a musical instrument, etc.

Both types of activities involve integration of and transformations between sensory and motor processes.  It has been difficult to separate the contributions from these two domains (sensory and motor) in the studies of motor control. In this talk I will show that it is possible to separate these contributions in data from both instrumental and complex actions by studying complementary automatic and intended components of the motion. My research has revealed that automatic components systematically co-vary with changes in dynamics. In contrast, intended components remain invariant to changes in dynamics and conserve regularities and law-like relations across families of acts.

I will provide evidence from behavioral, neural and clinical data to show that sensory and motor processes are separable in natural acts and to suggest that the contributions from the sensory component that remain robust to changes in movement dynamics can be used to define cognitive processes. Implicit in these results is the ability to objectively assess the disruption of cognitive processes through the study of natural motions of daily living and to quantify performance gains through manipulations of sensory guidance. We are already effectively applying these results in patients (stroke and Parkinson’s disease) and in individuals with Autism Spectrum Disorders (ASD).