EAGER: Modifying human cognition using targeted non-invasive stimulation of large-scale brain networks

University Of Texas At Dallas, Richardson TX

Investigators

Abstract

Cognitive abilities differ across individuals. These differences are present across individuals with different status of health, but also within seemingly homogenous cohorts such as healthy young adults. Individual differences in cognition are typically differentiated according to distinct domains of processing (e.g., long-term memory, executive function, language, perception). These distinctions are thought to be a result of the functional specialization of dissociable systems, or networks, in the human brain. This project investigates whether a specific cognitive ability can be modified by directly manipulating its corresponding brain system. The study involves the development and application of "network-guided" non-invasive brain-stimulation to enhance specific cognitive abilities in healthy young adults; specifically, executive function and long-term episodic memory. The results of the research will inform our understanding of the biological source of individual differences in cognition and possibly provide an approach for modifying cognitive ability within an individual. In doing so the project will help us further understand the brain mechanisms that mediate cognitive dysfunction in impaired individuals across the lifespan, and may allow application of the research program towards delaying or even preventing cognitive dysfunction in vulnerable individuals, using brain stimulation. The project includes mentorship to a post-doctoral fellow, sharing of tools and methods that are developed in relation to the project, and engagement in outreach and education activities with the general public. Previous work has used brain stimulation to modify various aspects of cognition across numerous target locations in the brain. The outcome and success of these studies have been variable but encouraging. Where stimulation-associated gains in cognitive ability have been noted, there has been sparse evidence linking the behavioral change to changes in the underlying neurophysiology, thus leaving a gap in our understanding of the underlying mechanism of change. The proposed research aims to elucidate whether and how non-invasive stimulation of the human brain can enhance specific domains of cognition (executive function and long-term episodic memory). Transcranial magnetic stimulation (TMS) sessions will target critical areas (network nodes) within two functional brain systems that have been implicated in each cognitive domain (frontal-parietal control system and default system, respectively). To characterize cognitive and brain changes, the study will incorporate extensive cognitive testing and measurement of brain network organization using functional magnetic resonance imaging (fMRI), collected both prior to and following the multiple TMS sessions. To accomplish the proposed aims, the project brings together methodological advances that the PI has helped pioneer. These methods allow precise characterization of brain stimulation targets on a subject-by-subject basis, and formal methods for characterizing and assessing changes in brain network organization observed at rest in an individual. By targeting specific features of brain organization and measuring their change as a result of stimulation, the broader goal of the proposed work is to gain a deeper understanding of how brain stimulation may modify cognition and the brain's functional network organization.