ABSTRACT
The interdisciplinary researches for a scientific explanation of consciousness constitute one of the most exciting challenges of contemporary science. However, although considerable progress has been made in the neurophysiology of states of consciousness such as sleep/waking cycles, investigation of subjective and objective nature of consciousness contents raises still serious difficulties. Based on a wide range of analysis and experimental studies, approaches to modeling consciousness actually focus on both philosophical, non-neural and neural approaches. Philosophical and non-neural approaches include the naturalistic dualism model of Chalmers, the multiple draft cognitive model of Dennett, the phenomenological theory of Varela and Maturana, and the physics-based hypothesis of Hameroff and Penrose. The neurobiological approaches include the neurodynamical model of Freeman, the visual system-based theories of Lamme, Zeki, Milner and Goodale, the phenomenal/access hypothesis of Block, the emotive somatosensory theory of Damasio, the synchronized cortical model of Llinas and of Crick and Koch, and the global neurophysiological brain model of Changeux and Edelman. There have been also many efforts in recent years to study the artificial intelligence systems such as neurorobots and some supercomputer programs, based on laws of computational machines and on laws of processing capabilities of biological systems. This approach has proven to be a fertile physical enterprise to check some hypothesis about the functioning of brain architecture. Until now, however, no machine has been capable of reproducing an artificial consciousness.