While the authors present compelling arguments to support that iGBR is an artifact of microsaccades, the role of microsaccades in visual information processing, especially their possible functional relationship with intrinsic neuronal oscillations remain to be elusive. Although the main result is extremely important and clears the mist around the "cognitive-gamma", the most interesting aspect is whether microsaccades contribute to information sampling or not, and whether this sampling is aligned to any neuronal oscillations or not. The study is eye opening but cries for a systematic investigation of microsaccades. For example, an analysis of microsaccades in response to a diverse set of visual stimuli, applying spectral analysis and coherency analysis with LFP would be necessary to elucidate the link. Most we know about microsaccades are that they have an average <1 Hz irregular occurrence and evoked by the low retinal slip during the random fixational motions of the eye (Engbert and Mergenthaler, 2006). However, microsaccades don't seem to be random. If you look at Yuval-Greenberg et. al. Supplementary Fig.2, the microsaccade geometry and temporal distribution appear to be highly regular. Just now that we are able to separate the the microsaccade-induced iGBR from physiological gamma starts the story to be interesting.
Copyright JournalFire 2013