Humans are remarkably adaptable — we can instinctively change a planned course of action if an unexpected event occurs (slamming on the breaks when a car swerves ahead), rapidly learn new skills (children developing language), and deftly compensate for loss of function (recovering after a stroke). Critically, this flexibility in behavior and control, while variable in its effectiveness, is present throughout the lifespan. The research in Dr. Jessica R. Cohen’s lab investigates how distinct brain networks interact and reconfigure when confronted with changing contexts, and how this neural flexibility contributes to flexibility in control and the ability to learn. Moreover, Dr. Cohen’s lab seeks to understand the consequences of dysfunction in this flexibility.
The Cohen Lab utilizes functional neuroimaging to characterize how functional brain networks interact and flexibly reconfigure in a range of contexts, such as changing cognitive demands, transformations across typical development, and disruptions in healthy functioning due to disease. They apply cutting edge multivariate methods from neuroscience, psychology, and mathematics, such as functional and resting state connectivity, graph theory, machine learning, and computational modeling. These methods enable the quantification of rapid, dynamic changes across the entire brain simultaneously, as well as the ability to specify the roles of individual brain regions or functional connections. Dr. Cohen’s lab applies these powerful methodological tools to multiple populations, such as healthy young adults, typically developing children, and patients. With this research strategy, they have elucidated important aspects of human cognition, development, and disease, such as how people can maintain focus while ignoring irrelevant events, why adolescents are particularly predisposed to risk-seeking, and what mechanisms of dysfunction underlie impulsive behavior in disorders such as ADHD. The ultimate goal of The Cohen Lab to illuminate the neural mechanisms underlying both successful and dysfunctional behavioral flexibility, learning, and control.
In a recent study, Dr. Cohen and her collaborators at UC Berkeley collected functional MRI data from healthy young adults and measured whole-brain functional network organization using graph theory, where each brain region was defined as a “node” of the brain graph, and each functional connection as an “edge”. With this technique, they were able to quantify the degree to which interactions across networks changed when cognitive demands changed. During a simple motor execution task, distinct brain networks became more segregated from each other and the network of brain regions underlying motor execution became more strongly interconnected within itself. The participants also completed a complex memory task that required input from multiple networks, such as those involved in visual perception, attention, and memory. During this memory task, integration across those distinct networks increased. These results underscore the human brain’s ability to selectively and adaptively reconfigure network organization when confronted with changing cognitive demands.
In another study, Dr. Cohen and her collaborators at Johns Hopkins University sought to determine whether dysfunctional brain network organization was the root of common symptoms in ADHD, such as impulsivity and inattention. Again they collected functional MRI data, this time from typically developing children and children with ADHD aged 8-12. They measured whole-brain functional network organization and found that typically developing children, like adults, displayed integration across distinct networks when resting (at baseline), while children with ADHD had a more segregated network structure at rest. Moreover, children with ADHD were less able to reconfigure network organization during a motor control task than typically developing children—and that inability to adaptively reconfigure was related to poorer behavioral performance and more symptoms related to ADHD. These results help us to understand what brain-related dysfunction underlies ADHD symptoms, and can lead to the development of treatments that specifically target that dysfunction.
Dr. Cohen’s lab is currently working on understanding how neural flexibility changes throughout typical development, and how stimulant medication may successfully treat children with ADHD by normalizing dysfunctional connectivity.
Dr. Jessica R. Cohen is an Assistant Professor in the Cognitive Area of the Department of Psychology and Neuroscience, and affiliated with the Biomedical Research Imaging Center and the Carolina Institute for Developmental Disabilities. For more information about the Cohen Lab, please visit them online.