ABSTRACT
Vision can be defined as a quasi-perceptual experience occurring in the absence of actual physical input, for example by seeing something “in the mind’s eye.” It involves a remarkable built-in human faculty that can, in effect, assign reality status to things that humans conceive only through their internal rather than their physical senses. This capacity is due in part to the brain being hard-wired to process actual perception (of the world) and mental imagery (e.g. internal vision) in the same neural regions, using similar processing mechanisms. This chapter offers a brief overview of the relevant neuroscientific research with regard to five broad themes: (a) the definition and significance of mental imagery; (b) the neurobiological mechanism underlying mental imagery and its role in human cognitive functioning; (c) the different sources, types and modalities of mental imagery; (d) the interaction between the external and the internal senses, and the optimal conditions for mental imagery; (e) the relationship between mental imagery and altered states of consciousness.
