UNIVERSITY PARK, Pa. — Tarkeshwar Singh, associate professor of kinesiology in the Penn State College of Health and Human Development, has been awarded a Faculty Early Career Development (CAREER) award from the U.S. National Science Foundation (NSF). The five-year, $775,450 CAREER award will support Singh’s research on the interaction between cognition, decision-making and motor control to plan and coordinate complex movement sequences and skills.
“Complex skills, from performing surgery to flying a jet, are built from long sequences of eye and hand movements that the brain must organize into a smooth, accurate performance,” said Singh, who’s also affiliated with the Huck Institutes of the Life Sciences. “But these sequences are fragile. A single distraction, such as an unexpected sound, can pull the gaze off course and disrupt the flow of movement.”
With this award, Singh will study how the brain builds and protects these complex, coordinated sequences and how it responds to distractions that compete for attention. The project focuses on working memory, or the brain’s short-term storage system, which is central to the process of building coordinated movement sequences. However, there are limits to how much information it can hold, Singh explained. To work around these limitations, the project will test the idea of hierarchical compression.
“The brain overcomes the narrow limits of working memory by grouping individual movements into larger memory units, a process called chunking,” Singh said. “These chunks are what allow neighboring movements to blend smoothly into one another rather than being executed as separate, stop-and-start actions.”
Singh and his collaborators will develop a computational framework to understand the moment-to-moment relationship between gaze and hand movement and how attention is organized. Using the robotic arm, study participants perform a series of reaching movements similar to sliding a computer mouse. The robot records information on the position, speed and force of the hand a thousand times per second. An eye-tracking device will measure eye gaze five hundred times per second and brain activity will be recorded by electroencephalography (EEG).
These signals will be recorded simultaneously, making it possible to study these processes in real time. This will allow the researchers to examine how working memory organizes the planning and execution of movement sequences, how visual information can disrupt the translation of memory into coordinated action and how movement changes attention and memory.
“The electrical signature of working memory changes in specific ways with how much is being held in mind, consistently enough to be measured in real time,” Singh said. “That gives an independent estimate of memory load as it rises and falls, which can be checked against what the eyes and hands are doing at that same instant. No single measure settles the question on its own. Three that can be lined up against each other, moment by moment, make for a much stronger case.”
With these insights through computational modeling and neural recordings, the research uncovers how the brain turns limited memory into skilled action. Because of this, researchers can begin to learn more about conditions that impair memory and movement together, such as stroke, Parkinson's disease, and traumatic brain injury. Studying how vision, memory and movement normally work together will help researchers understand what goes wrong when these processes fail to coordinate, according to Singh.