The brain's sensory systems are continually bombarded by a flurry of environmental information, such as shapes, colors, textures, sounds, and smells. In fact, there is far more information than the brain can process simultaneously. As a result, there is an ongoing competition for the brain's limited processing resources. With funding from the National Science Foundation, Dr. John Foxe and his research team are investigating the link between oscillatory signatures of selective attention in electroencephalography (EEG) recordings and the microstructure of long-range connections between brain networks that have been previously implicated in spatial selective mechanisms. The most frequently investigated mechanism of selective attention is spatial selection, where one location in the environment receives preferred processing relative to other locations. An observable signature of spatial selection is increased oscillatory amplitude of brain electrical activity within a particular frequency band, alpha (approximately 10 Hz), over brain regions that process task-irrelevant locations. These oscillations can be imagined as a sine wave, with the peaks and troughs of the sine wave representing relative increases and decreases in neural excitability. Using experimental tasks in which participants are cued to attend to one region of space, while simultaneously ignoring distracting stimuli in other regions of space, Dr. Foxe is EEG measures and structural measure of the brain's long-range connections obtained using diffusion tensor imaging (DTI). Dr. Foxe is leveraging the wide variability across individuals in both oscillatory indices of spatial selection as well as the microstructure of neuronal circuits connecting far-flung brain networks. The coordination of these two neuroimaging techniques (EEG and DTI), as well as the use and exploration of individual differences in brain oscillations and structure, represent novel approaches to the study of selective attention. This work aims to help us understand the relevance of neural oscillations in sensory selection and guide the further development of hypotheses regarding the neural mechanisms employed by networks of selective attention.
Dr. Foxe's laboratory has a long record of translational research. The results of the present studies will provide foundational understanding from which to launch investigations into impairments of attentional selection within clinical populations. Selective attention is disordered in several clinical populations, including individuals with spatial neglect after stroke, attention deficit hyperactivity disorder (ADHD), autism spectrum disorder (ASD), and schizophrenia. In addition, the researchers' use of multiple methodologies (EEG and DTI) will provide an excellent training opportunity for graduate students and postdoctoral fellows. An expertise in multiple methodological approaches, each with their unique strengths and weaknesses, is becoming more and more important for a successful career in the neurosciences. A thorough understanding of the increasingly complex questions being addressed in the neurosciences requires converging findings from more than one experimental tradition. Comprehensive training in imaging techniques in humans will thus provide a terrific base from which to build a successful research career.
