GWT has adapted to new waves of evidence, especially brain evidence.

Based on today’s far more detailed understanding of the brain, GWT has adapted to new waves of evidence.

The brain-based version of GWT is called Global Workspace Dynamics (GWD) (Baars et al., 2013; Baars and Geld, 2019) precisely because the cortex is viewed as a “unified oscillatory machine” (Steriade, 1999).

A wide range of experimental and theoretical studies in the field of consciousness emphasize the complex and rapid interactivity of numerous regions and connectivities in the C–T core.

Global Workspace Dynamics of conscious experience is supported by brain evidence, particularly the role of the cortex and thalamus.

While the cortex and thalamus look separate to the naked eye, they act as an integrated system (Llinás and Paré, 1991; Edelman and Tononi, 2000; Steriade, 2006; Freeman, 2007). That dynamical view of the C–T core should give us pause about proposing dichotomies that may not be in evidence.

**Stan Franklin and colleagues have built on GWT to sketch out a more general theory of cognition in LIDA, a computational implementation of GWT (Franklin et al., 2012).**

The Dehaene-Changeux Model (DCM) and Global Neuronal Workspace Theory (GNWT) are part of the larger GW “family” of related theories.

Nobelist Gerald M. Edelman and Giulio Tononi proposed a very compatible brain based theory of consciousness in the year 2000, and Global Workspace Dynamics brings those two streams of science up to date. Stanislas Dehaene and Jean-Pierre Changeux in Paris have developed experimentally testable models and made further testable claims about the brain basis of visual consciousness (Dehaene et al., 1998; Dehaene and Changeux, 2011).

Stan Franklin and colleagues have built on GWT to sketch out a more general theory of cognition in LIDA, a computational implementation of GWT (Franklin et al., 2012). GWT therefore joins other theories in viewing consciousness as the product of highly integrated and widespread cortico-thalamic (C-T) activity, following a long trail of evidence (Dehaene et al., 1998).

These theoretical ideas provide a useful framework for our rapidly accumulating body of evidence.

They are consistent with our current knowledge, and can be enriched to include other aspects of human experience. GWT neither denies nor asserts the dominance of any anatomical region; it is focused on the dynamic functioning of the cerebral cortex, and does not partition the cortex into static prefrontal and posterior divisions. Brain anatomy gives a necessary (but not sufficient) account of Global Workspace Dynamics.

The wiring of the cortex and thalamus is bi-directional. (If neuron A leads to B, B will generally also lead to A.)

GWT predicts widespread “integration and broadcasting” of conscious experiences. These have been observed in brain experiments that we examine in this course.

Conscious experiences may combine multiple gestalt layer in the same experience, like your conscious understanding of this page, which combines visual letter shapes, letters, words and phrases in single visual fixations.

Observable “ignitions” (broadcasting) in the visual cortex seem to combine several related neural populations.

Sources:

Image 1: Dehaene S, Changeux JP. Experimental and theoretical approaches to conscious processing. Neuron. 2011 Apr 28;70(2):200-27.

Image 2: Franklin, S., Strain, S., Snaider, J., McCall, R., and Faghihi, U. (2012). Global workspace theory, its LIDA model and the underlying neuroscience. Biol. Inspir. Cogn. Architect. 1, 32–43. doi: 10.1016/j.bica.2012.04.001

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