History and News in the Human Visual Cortex

In the search for unifying principles of human visual cortex function- it will be proposed that human cortical dynamics can be viewed as shifting between two modes.  The first is the well-studied active-mode, informing about visual "News"- i.e. the current perceptual state of the observer.  These signals are characterized by fast "ignitions" of highly selective neuronal activity.  The second, still poorly understood resting- mode is characterized by slow and wide-spread spontaneous fluctuations.  It will be hypothesized that these signals inform about the "History"-i.e. the accumulated statistics of prior cortical activations. Examples of these two modes will be shown- derived from single neurons, local field potentials and functional magnetic resonance imaging (fMRI).  Preliminary evidence supporting their functional significance will be presented.