A neuronal model of a global workspace in effortful cognitive tasks

TLDR

The authors propose a minimal hypothesis that effortful tasks engage a global workspace and predict that dorsolateral prefrontal cortex and anterior cingulate will show distinct spatio‑temporal activation patterns during imaging. The model posits a global workspace of highly interconnected neurons that mobilize when specialized perceptual, motor, memory, evaluative, and attentional processors are insufficient, selectively modulating processor activity via descending connections and forming variable spatio‑temporal coactivation patterns influenced by vigilance and reward signals. Simulation of the Stroop task demonstrates that workspace activation rises during novel task acquisition, effortful execution, and after errors.

Abstract

A minimal hypothesis is proposed concerning the brain processes underlying effortful tasks. It distinguishes two main computational spaces: a unique global workspace composed of distributed and heavily interconnected neurons with long-range axons, and a set of specialized and modular perceptual, motor, memory, evaluative, and attentional processors. Workspace neurons are mobilized in effortful tasks for which the specialized processors do not suffice. They selectively mobilize or suppress, through descending connections, the contribution of specific processor neurons. In the course of task performance, workspace neurons become spontaneously coactivated, forming discrete though variable spatio-temporal patterns subject to modulation by vigilance signals and to selection by reward signals. A computer simulation of the Stroop task shows workspace activation to increase during acquisition of a novel task, effortful execution, and after errors. We outline predictions for spatio-temporal activation patterns during brain imaging, particularly about the contribution of dorsolateral prefrontal cortex and anterior cingulate to the workspace.