The majority of brain activity is considered spontaneous because it does not occur in response to an external event. Researchers do not know how this inherent activity, whose spatial pattern is called the functional connectome, influences cognition. As a result, its role in mental disorders remains elusive.
“The functional connectome measures to what degree regions in the brain are connected to each other at any given time,” said Sepideh Sadaghiani, an assistant professor of psychology. “There is an overall stable structure to functional connectivity, but there is some variability over time. We don’t know what that variability means for cognition.”
A grant from the National Institute of Mental Health—part of the National Institutes of Health — will provide $2 million over five years to fund research on the functional role of this variability. Sadaghiani is the primary investigator on the grant.
Traditionally, the functional connectome has been studied using functional magnetic resonance imaging (fMRI), which investigates neural connections across the whole brain. However, this is an indirect measurement of neural activity with limited temporal resolution and can further be influenced by artifacts.
The project, “Cognitive Significance of Functional Connectome States,” aims to understand how the functional connectome influences cognition using more direct methods such as electroencephalography (EEG) along with fMRI.
“fMRI only images slow neural processes. The novelty that we have suggested is to also use EEG so that we can see the faster neurobiological processes,” Sadaghiani said.
Sadaghiani is interested in using paradigms in which repeated presentation of the same stimulus may generate two types of behavioral outcomes.
“One example is using a simple sound stimulus and adjusting the volume to your personal threshold prior to the experiment. If I play this very faint sound repeatedly, sometimes you will hear it and sometimes you will not. The stimulus is not changing but your perception is. This allows us to see what is different in the functional connectome and how that affects behavior,” Sadaghiani said. Establishing a link between cognition and connectome function will help identify markers and treatment targets for mental illnesses.
Sadaghiani will collaborate with Beckman faculty members Wendy Heller, a professor of psychology; Brad Sutton, a professor of bioengineering and the technical director of Beckman’s Biomedical Imaging Center; and Sanmi Koyejo, an assistant professor of computer science.