To successfully navigate through the world, our brain needs to know where our body is and how our body’s position changes as we move. Amanda S. Therrien, PhD, has been awarded a Standard Grant from the National Science Foundation (NSF) to conduct an innovative study that will help us better understand the processes our brains use to estimate where the body is in space and how sensory predictions and perceptions may influence movement.
Dr. Therrien directs the Sensorimotor Learning Laboratory at Jefferson Moss Rehabilitation Research Institute and is an Assistant Professor of Rehabilitation Medicine at Thomas Jefferson University. As Principal Investigator, she will lead this three-year grant, titled “The Role of Sensory Predictions in Updating Perception and Action,” beginning in August of this year. This grant is the first-ever NSF grant awarded to an investigator at our Institute, and the project will contribute to answering longstanding questions in the field about how the brain combines predictions and feedback signals to estimate body position and how it changes with movement (i.e., the body state).
Feedback from our senses, particularly vision and proprioception, constantly provides the brain with information on our body state. However, these sensory systems process information relatively slowly, so the information our brain receives about our body position is always delayed in time. To compensate for the time delay, researchers have hypothesized that the brain generates predictions of the sensory consequences of movements to anticipate and correct errors before sensory feedback is available.
Dr. Therrien’s research aims to shed light on how the brain combines predictions and feedback signals to estimate the body’s state. This dynamic process is something we all experience every day. Our sensory predictions must constantly be updated when the physics of our bodies and our surroundings change — for example, when you put on a heavy coat or suddenly step on a slippery surface. Sensory predictions are kept up-to-date through a learning process called motor adaptation. By updating sensory predictions, motor adaptation has the effect of altering movement. Growing evidence suggests that sensory perception also changes after motor adaptation, but it is unclear whether this perceptual update is also driven by learning new sensory predictions or another sensory updating process.
The research funded by this NSF award is designed to answer three important questions:
1) Do sensory predictions differently inform our perceptions of body position versus movement?
2) Do updated sensory perceptions show similar characteristics to updated movements following motor adaptation (e.g., context dependence)?
3) Do updated sensory perceptions following motor adaptation themselves meaningfully impact our movement?
Results from this research will provide valuable insights into the circumstances under which sensory predictions contribute to body state estimates and sensory perception, and Dr. Therrien’s findings could potentially change our current theoretical models of how these signals influence movement.
This line of research is relevant for advancing our fundamental understanding of the neural control of movement, but it also has implications for rehabilitation in individuals with neurological conditions. We know that the ability to make accurate sensory predictions is impaired in individuals who have had a stroke or have cerebellar ataxia, a condition in which damage or dysfunction in the cerebellum results in poor balance, coordination, and muscle control. Improving our knowledge of how information from different sources is integrated by the brain to influence movement may help identify new approaches for neurorehabilitation in the future.