Poster E9, Monday, March 27, 2:30 – 4:30 pm, Pacific Concourse
Spatial selectivity and attentional modulation reflect coordinated processing of high frequency broadband and alpha signals in the human visual system
Anne Martin1, Liang Wang1,2, Yuri B. Saalmann1,3, Avgusta Shestyuk4, Nathan E. Crone5, Josef Parvizi6, Robert T. Knight4, Sabine Kastner1; 1Princeton University, 2Chinese Academy of Sciences, 3University of Wisconsin – Madison, 4University of California Berkeley, 5The Johns Hopkins Hospital, 6Stanford University School of Medicine
Classical effects of attention on low frequency (alpha) suppression have been characterized in human EEG, and high frequency spiking activity has been investigated in many animal neurophysiology studies. However, detailed electrophysiological analyses on spatial selectivity and the effects of attention across these frequency domains in the human brain have not been reported. We analyzed ECoG signals recorded from 8 epilepsy patients performing an Eriksen flanker task variant. Following a spatial cue and variable delay interval, subjects differentiated between two shapes at the cued location in an array of distracters, allowing us to measure selectivity within 25 degrees of visual angle. Using our probabilistic atlas of the human visual system (Wang et al., 2014), we localized electrodes to visual topographic areas and identified those with cue-evoked spatially-selective high frequency broadband power (HFB) or low frequency (alpha) suppression. We found that HFB and alpha spatial selectivity lasted into the delay as well as through the target array interval in higher-order areas of both the ventral and dorsal visual processing streams. In these areas, the HFB response field center was strongly correlated with the location of strongest alpha suppression. Further, the temporal progression of HFB and alpha selectivity indicate a specific, coordinated representation of space in low and high frequency bands, suggesting an organized functionality of processing that may facilitate information transfer across these cortical areas. Wang L, Mruczek RE, Arcaro MJ, Kastner S (2014) Probabilistic Maps of Visual Topography in Human Cortex. Cerebral Cortex:bhu277.
Topic Area: ATTENTION: Spatial