Coupling between spontaneous (resting state) fMRI fluctuations and human oculo-motor activity.

The recent discovery of incessant spontaneous fluctuations in human brain activity (also termed resting state fMRI) has been a focus of intense research in brain imaging. The spontaneous BOLD activity shows organized anatomical specialization as well as disruption in a number of brain pathologies. The link between the spontaneous fMRI fluctuations and human behavior is therefore of acute interest and importance. Here we report that a highly significant correlation exists between spontaneous BOLD fluctuations and eye movements which occur subliminally and spontaneously in the absence of any visual stimulation. Of the various eye movement parameters tested, we found robust and anatomically consistent correlations with both the amplitude and velocity of spontaneous eye movements. Control experiments ruled out a contribution of spatial and visual attention as well as smooth pursuit eye movements to the effect. The consistent anatomical specificity of the correlation patterns and their tight temporal link at the proper hemodynamic delay argues against a non-neuronal explanation of the effect, such as cardiac or respiratory cycles. Our results thus demonstrate a link between resting state and spontaneously emerging subconscious oculo-motor behavior.