The global workspace

24/03/2009 by admin.

There is a good description of the global workspace model of consciousness quoted below. It comes from the paper mentioned in the last post, Gaillard’s Converging Intracranial Makers of Conscious Access (here).

“This model, in part inspired from Bernard Baars’ theory, proposes that at any given time, many modular cerebral networks are active in parallel and process information in an unconscious manner. Incoming visual information becomes conscious, however, if and only if the three following conditions are met: Condition 1: information must be explicitly represented by the neuronal firing of perceptual networks located in (sensory) areas coding for the specific features of the conscious percept. Condition 2: this neuronal representation must reach a minimal threshold of duration and intensity necessary for access to a second stage of processing, associated with a distributed cortical network involved in particular parietal and prefrontal cortices. Condition 3: through joint bottom-up propagation and top-down attentional amplification, the ensuing brain-scale neural assembly must “ignite” into a self-sustained reverberant state of coherent activity that involves many neurons distributed throughout the brain.

Why would this ignited state correspond to a conscious state? The key idea behind the workspace model is that because of its massive interconnectivity, the active coherent assembly of workspace neurons can distribute its contents to a great variety of other brain processors, thus making this information globally available. The global workspace model postulates that this global availability of information is what we subjectively experience as a conscious state. Neurophysiological, anatomical, and brain-imaging data strongly argue for a major role of prefrontal cortex, anterior cingulate, and the associative areas that connect to them, in creating the postulated brain-scale workspace.”

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