Therrien Research

Dr. Therrien is the director of the Sensorimotor Learning Laboratory at Jefferson Moss Rehabilitation Research Institute. The primary goal of her research is to improve motor rehabilitation protocols for individuals with neurological disorders (e.g., cerebellar ataxia, stroke) by enhancing our understanding of the precise sensory and motor control mechanisms that underlie their behavioral impairment(s). Her research employs robotic technology and 3-D motion capture integrated with virtual reality to perform detailed motion tracking of the body.

Understanding cerebellar contributions to model-based and model-free mechanisms of motor learning

The process of learning a new movement is supported by a suite of interacting neural mechanisms. Model-based motor learning is thought to employ internal representations (i.e., models) of the body, environment, and/or task dynamics. It is most often associated with sensory-prediction-error-dependent adaptation, and permits rapid learning and flexible behavior. Model-free motor learning describes the acquisition of inflexible stimulus-response associations and is often linked with reinforcement learning. A popular hypothesis states that the cerebellum generates and stores internal models, making it crucial for model-based motor learning. In support of this hypothesis, cerebellar damage impairs sensory-prediction-error-dependent adaptation. However, the degree to which the cerebellum may play a role in model-free motor learning remains unclear. In this line of research, we study individuals with damage to the cerebellum and neurologically healthy individuals to test the precise ways in which cerebellar damage disrupts various mechanisms of motor learning. 
 

Understanding cerebellar and parietal contributions to body state estimation

Body state estimation describes the process of computing the current position and/or movement (i.e., position changing over time) of the body. It is critical to proper movement control, being necessary for the initial computation of movement commands as well as the correction of movement errors. The cerebellum and parietal cortex have long been associated with body state estimation. Yet, damage to the cerebellum causes a pattern of sensory and motor impairments that differs widely from the sensory-motor effects of parietal damage. This suggests that each brain region may serve distinct, but complementary state estimation roles. In this line of research, we study individuals with damage to the cerebellum, individuals with damage to regions of the parietal cortex, and neurologically healthy individuals as they perform various movement and sensory perception tasks. Through detailed comparison across these groups, we aim to elucidate the mechanisms underlying body state estimation.