Provided for Non-commercial Research and Educational Use. Not for Reproduction, Distribution or Commercial Use. Author's Personal Copy Introduction Definition of Bns Building Models Using Models Special Cases Further Reading

The aim of this chapter is to examine formal models, expressed in terms of neuronal networks, that link together the molecular, neuronal, physiological, and behavioral/mental data on access to consciousness. Ultimately implemented as ‘formal organisms,’ these neurocomputational models should altogether account for the available data and produce experimentally testable predictions at all of those levels. They deal with the subjective experience of the access to a unified or global workspace where a synthesis between past, present, and future takes place: multimodal perceptions, emotions, and feelings (present); evoked memories of prior experiences (past); and anticipations of actions (future) become subjectively integrated in a continuously changing and dynamic flow of consciousness. The hypothesis of the neuronal workspace emphasizes the role of distributed pyramidal neurons with long-distance connections, particularly dense in prefrontal, parietal, and cingulate regions, in the global interconnection of multiple specialized processors. We show that the dynamics of the model lead to the spontaneous and sudden formation of conscious ‘global’ activity states which can be broadcasted to many processors. Our framework has been applied to a number of well-defined cognitive tasks and captures some of the available data on the relationship between subjective reports and objective physiological and brain imaging measurements in paradigms such as masking and the attentional blink.