Scalp-Recorded Induced Gamma-Band Responses to Auditory Stimulation and Its Correlations with Saccadic Muscle-Activity
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We previously showed that the transient broadband induced gamma-band response in EEG (iGBRtb) appearing around 200–300 ms following a visual stimulus reflects the contraction of extra-ocular muscles involved in the execution of saccades, rather than neural oscillations. Several previous studies reported induced gamma-band responses also following auditory stimulation. It is still an open question whether, similarly to visual paradigms, such auditory paradigms are also sensitive to the saccadic confound. In the current study we address this question using simultaneous eye-tracking and EEG recordings during an auditory oddball paradigm. Subjects were instructed to respond to a rare target defined by sound source location, while fixating on a central screen. Results show that, similar to what was found in visual paradigms, saccadic rate displayed typical temporal dynamics including a post-stimulus decrease followed by an increase. This increase was more moderate, had a longer latency, and was less consistent across subjects than was found in the visual case. Crucially, the temporal dynamics of the induced gamma response were similar to those of saccadic-rate modulation. This suggests that the auditory induced gamma-band responses recorded on the scalp may also be affected by saccadic muscle activity.
KeywordsEEG Induced gamma Auditory Human Saccades Microsaccades High frequency Spike potential
The first author is partially funded by the National Postdoctoral Award Program for Advancing Women in Science (Weizmann Institute of Science) and is grateful for this support. The study was supported by an extended grant from the National Institute of Psychobiology in Israel, founded by the Charles E. Smith family, to L.Y.D. We are indebted to Prof. Avital Deutsch for the use of the eye tracker and for helpful advice, and to Ruth Levy for her invaluable contribution to data collection.
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