Ed Awh (Institute for Mind and Biology, Chicago): Tracking the spatial and temporal dynamics of online spatial representations with rhythmic brain activity
Event Date and Time:
Thursday, September 14, 2017 - 3:30pm to 5:30pm
Bioscience Research Building 1103
About the Speaker
Edward Awh, Ph.D. is Professor in the Department of Psychology and The College. He is a member of the Grossman Institute for Neuroscience, Quantitative Biology, and Human Behavior.
Awh received a BA in Psychology from Northwestern University and MA and Ph.D. in Psychology from University of Michigan. He completed his dissertation research in the laboratories of John Jonides and Edward E. Smith at Michigan. Awh did his postdoctoral research at the Center for Human Information Processing at University of California, San Diego.
Prior to UChicago, Awh held a faculty appointment in the Department of Psychology and the Institute for Neuroscience at University of Oregon.
About the Presentation
Abstract: A substantial body of evidence suggests that neural activity in the alpha frequency band (8-12 Hz) covaries with the locus of covert spatial attention, such that attention to one visual field yields a sustained decline in alpha power at contralateral electrode sites. In our work, we have exploited this covariation by using an inverted encoding model to reconstruct spatial response profiles (termed channel tuning functions, or CTFs) based on the topography of alpha activity on the human scalp. Thus, in a task that required the storage of locations in working memory, we observed a graded profile of activity across spatial channels that peaked at the stored location during both the encoding and delay periods of the task. These spatial CTFs provide an opportunity to quantify the basic tuning properties of online spatial memories to examine how the precision of neural representations changes with manipulations of the probability of storage or the number of items stored. In addition, I’ll show that the same method can be used to track the locus and timing of covert attention, as well as the retrieval of spatial representations from long term memory. These findings demonstrate the integral role that alpha band activity plays in the online representation of space, and provide a powerful new approach for tracking these representations during during ongoing cognition and without requiring overt behavioral responses.