Mechanisms of Attentional Control Revealed by Temporal Fluctuations in Neural Activity

University Of New Hampshire, Durham NH

Investigators

Abstract

The human eyes collect vastly more visual information than the brain can possibly process, and consequently, attention is required to prioritize stimuli that are relevant while ignoring those that are not. Previous work has shown that humans possess the capacity to voluntarily direct attention to behaviorally important objects, features, or locations, but they are also susceptible to having their attention captured involuntarily by salient, irrelevant stimuli. With funding from the National Science Foundation, Andrew B. Leber, Ph.D., of the University of New Hampshire, is carrying out research to learn how humans achieve a balance between the voluntary and involuntary components of attention. His research is using functional magnetic resonance imaging (fMRI) to shed light on this important issue, addressing two specific aims. The first aim is to determine whether individuals fluctuate over time in exerting voluntary attention and experiencing susceptibility to involuntary attention. A novel methodological approach is introduced in which baseline fluctuations in neural activity reflected in the fMRI signal are tracked in order to predict in advance moment-to-moment fluctuations in behavioral indices of distractibility. This approach allows the discovery of brain regions used in voluntary and involuntary attention. The second aim is to understand how individuals can tip the balance between voluntary and involuntary components of attention. On the one hand, they can use a process of enhancement, by which the neural representation of relevant stimulus features is boosted, thereby reducing the impact of irrelevant stimulus salience. On the other hand, they can use a process of suppression, by which a known irrelevant distractor can be directly inhibited. The experiments being carried out are determining whether brain regions involved in overcoming distraction either enhance relevant information, suppress irrelevant information, or both. Ignoring distracting information is critical for successful completion of everyday tasks, from walking or driving to operating heavy machinery. This project is contributing to a greater understanding of how the brain overcomes visual distraction in order to allow healthy visual processing. The project also aims to contribute to efforts to better understand clinical disorders with an attention-related component, such as Alzheimer's disease, Attention Deficit Hyperactivity Disorder (ADHD), and Schizophrenia, all of which have previously been associated with abnormal fluctuations in brain activity and behavior. Beyond scientific impacts, this project provides valuable training opportunities at the University of New Hampshire, where it marks the introduction of advanced human neuroscience techniques. Graduate and undergraduate students engage in collection and analysis of fMRI data, and they assist in disseminating the results broadly, via presentation at international research conferences and publication in peer-reviewed journals. The research enriches the broader intellectual community at the University, as student and faculty colleagues benefit from the integration of the research into undergraduate courses and advanced seminars.