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Stephanie Nelli, Max Boonjindasup, Aayushi Malpani, John Serences; Alpha entrainment of posterior visual cortex impacts visual detection. Journal of Vision 2017;17(10):976. doi: 10.1167/17.10.976.
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Rhythmic neural activity in the alpha band (8-13 Hz) is thought to play an important role in the selective processing of sensory information. Posterior alpha oscillations seem to regulate visual information transfer, where increased alpha amplitude reflect a concurrent increase in inhibitory mechanisms and decreased perceptual sensitivity (Klimesch et al 2007 for review). Additionally, increases in alpha frequency have been associated with heightened perceptual sensitivity both between and within subjects (Samaha & Postle 2016). However, it is unknown how alpha frequency and amplitude interact to impact behavioral performance. Here we sought to determine how changes in power across the alpha range, including at each subject's peak alpha frequency, modulate perception. To do this, we entrained neural populations using steady-state visual evoked potentials (SSVEP) in the alpha range. While recording EEG, we asked subjects to detect a brief (~16 ms) increase in the luminance of a central black fixation dot surrounded by a circular checkerboard flickering at one of eight possible frequencies in the alpha range. During this recording session, we also measured peak alpha frequency while subjects rested with their eyes closed and with their eyes open. We confirmed that subjects showed significant entrainment at each alpha frequency in posterior channels. We then found that subjects showed reduced detection performance at frequencies below, but not above, their peak alpha frequency. This implies that increasing amplitude at the peak alpha frequency does not reduce perceptual sensitivity, and suggests a more nuanced relationship between alpha frequency and alpha power in the optimal transfer of visual information.
Meeting abstract presented at VSS 2017
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