Does conscious visual perception emerge globally within transcortical multi-level recursive neural networks or do such networks endow selective cortical areas with properties that locally engender particular conscious experiences?
Dan Pollen
Professor of Neurology,
Department of Neurology,
University of Massachusetts Medical Center
Abstract:
By the end of the twentieth century, a considerable body of evidence suggested that conscious sensory experience requires activation of at least some minimal recursive neural network (Grossberg, 1995; Pollen, 1999). However, the fundamental question as to whether any conscious visual experience is instantiated locally within a given cortical area within that recursive network or is an emergent property of neuronal activity across the entire loop remains unresolved. We now inquire as to whether such recursive processing is essential only for loops between extrastriate cortical areas explicitly representing experiences such as color or motion back to V1 or whether it is processing between the areas computing such explicit representations and still higher levels that is exclusively or additionally essential for visual experience (Pollen, 2003). If recursive processing is not essential for the emergence of conscious visual experience, then it should also be possible to determine whether it is only the intracortical sensory processing within areas computing explicit sensory representations that is required for perceptual experience or whether it is the subsequent processing of the output of such areas within more anterior cortical regions that engenders perception. The present analysis suggests that the questions posed here may ultimately become experimentally resolvable using techniques that combine electrical activation of afferent pathways with selective blocks of various recurrent pathways together with reversible inactivation of early cortical areas. Whatever the outcome, the results will likely open new approaches to identify the neural correlates of conscious visual perception.