The visual system and levels of perception: properties of neuromental organization.

To see whether the mental and the neural have common attributes that could resolve some of the traditional dichotomies, we review neuroscientific data on the visual system. The results show that neuronal and perceptual function share a parallel and hierarchical architecture which is manifest not only in the anatomy and physiology of the visual system, but also in normal perception and in the deficits caused by lesions in different parts of the system. Based on the description of parallel hierarchical levels of active information processing in the visual brain, we suggest a concept of dissociable levels of perception, advocating that the phenomenal perception and recognition is realized in the functional integrity of a network of reciprocal cortico-cortical connections. The properties shared by neuronal and perceptional functions provide a basis for a neuromental monism in which both functions are attributed a causal role.