Abstract:

Scale-free dynamics are exhibited by many complex processes in nature.  Despite long-held interests in fields such as physics and heart physiology, it has so far been largely neglected in mainstream neuroscience research, partly due to its universality.  In this talk I will show that underlying the same power-law distribution, the temporal structures of scale-free dynamics vary from one system to another.  This suggests that it is important to go beyond the mask of the power-law distribution and explore the fine spatiotemporal patterns and underlying mechanisms of scale-free brain activity.  I will further discuss recent findings demonstrating the functional significance of scale-free brain activity, obtained with both intracranial EEG and fMRI in humans.  Lastly, we have shown recently that the low-frequency end of scale-free brain activity, termed the “slow cortical potential”, is an electrophysiological correlate of the fMRI signal.  Its correlation with conscious awareness under various experimental conditions will be discussed.