Global Neuronal Workspace (GNW)

A hypothesis that offers a simple connectomic scheme based upon the contribution of neurons with long-range axons to conscious processing. Their reciprocal interactions contribute to the formation of a global workspace, broadcasting signals from the sensory periphery to the whole brain, thus yielding “conscious” experience. The GNW hypothesis privileges cortical pyramidal cells with long-range excitatory axons, particularly dense in prefrontal, temporoparietal, and cingulate regions, that, together with the relevant thalamocortical loops, reciprocally interconnect multiple specialized, automatic, and non-conscious processors. Another important feature of this hypothesis is that the GNW activates in a non-linear manner, called ‘‘ignition,’’ upon access to conscious processing. Ignition is characterized by the sudden, coherent, and exclusive activation of a subset of workspace neurons coding for the current conscious content, with the remainder of the workspace neurons being inhibited.