“One of the major errors in the Raccah et al. (2021) paper is that Raccah and his co-authors looked at the different brain regions as separate “neighborhoods,” without taking into consideration the functional interactions between its different parts.”
– Bernard Baars
We think of the cortex in terms of anatomical regions, but the cortex works as a whole. Static, gross anatomical divisions are superseded by the dynamical connectome of cortex.
This holistic viewpoint is detailed in the recent paper in the Journal Frontiers in Psychology: Consciousness Research, titled “Global Workspace Theory & Prefrontal Cortex: Recent Developments” (Baars, Geld & Kozma, 2021), which we discuss in this episode.
Our special guest for Episode 23 is Dr. Robert Kozma, professor and director of the Center for Large-Scale Integrated Optimization and Networks (CLION) at the FedEx Institute of Technology, and professor of Mathematics in the Department of Mathematical Sciences at the University of Memphis. Ilian Daskalov, our student interviewer, joins us to explore this recent paper on GWT and Prefrontal Cortex.
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 cortico-thalamic (C–T) core. That dynamical view of the C–T core should give us pause about proposing dichotomies that may not be in evidence. This paper aims to clarify some empirical questions that have been raised, and review evidence that the prefrontal and posterior regions support dynamic global workspace functions, in agreement with several other authors.
To follow along with this discussion, here is the link to the source paper: Baars, B. J., Geld, N., & Kozma, R. (2021). Global Workspace Theory (GWT) and Prefrontal Cortex: Recent Developments. Frontiers in Psychology, 12, 5163. https://doi.org/10.3389/fpsyg.2021.749868
Global Workspace Theory: A Theory of Human Cognitive Architecture, the Cortex, and Consciousness. A Brief Overview.
In this episode, we provide a brief overview of Global Workspace Theory (GWT), along with recent developments and clarifications of modern neuroscientific evidence. GWT started in the 1980s as a purely psychological theory of conscious cognition, and has become a prominent approach in scientific studies of consciousness.
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) precisely because the cortex is viewed as a “unified oscillatory machine”. 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.
Bernie clarifies what Global Workspace Theory predicts about consciousness. There is a widespread “broadcast” associated with consciousness in the brain. He points out that such a prediction was seen as a radical one, given that the general belief at the time was that attention is selective and therefore narrows input, selecting only what we have enough capacity to process.
Robert suggests that in science, metaphors are often useful, but never completely accurate. Metaphors have their limitations and interpreting them literally can lead to problems.
Bernie draws a distinction between anatomical and dynamic regions in the brain. He uses the metaphor of a city as an example, where the different neighborhoods represent the anatomical parts of a brain, and the flow of traffic represents the brain’s functional dynamics.
The GWT “Family” of Theories is Evidence-Driven
Consciousness studies have been undergoing rapid development, in part, due to new experimental techniques and brain monitoring. The GW “family” of theories has been at the forefront of these developments and continues to make novel predictions. Relevant mathematical advances are also emerging, including spatio-temporal dynamic network and graph theory.
Bernie explains that the unifying principle of the Global Workspace “family” of theories is the idea that there is a kind of a broadcast of conscious contents about a third of a second after sensory onset. For the first third of a second, there is a lot of unconscious processing in the brain.
Global Workspace Theory and the Cortico-Thalamic System
The idea that the prefrontal cortex is separate from the rest of the cortex is misleading. From a theoretical viewpoint, Baars et al. (2013) suggest that the cortico-thalamic system is inherently dynamic, a view also taken by Pribram (1991), Edelman and Tononi (2000), Freeman et al. (2008), Dehaene and Changeux (2011), Edelman et al. (2011), and others. If we view the epicenter of conscious events in cortex to be dynamic rather than anatomically static, the question of prefrontal involvement becomes more nuanced.
The trio examine what Raccah et al. (2021) got wrong when discussing Global Workspace Theory. “One of the major errors in that paper,” Bernie says, “is that Raccah and his co-authors looked at the different brain regions as separate “neighborhoods,” without taking into consideration the functional interactions between its different parts.” Robert draws attention to the misleading interpretation by Raccah et al. in treating the cortex as if there are separate compartments that don’t communicate with each other, most notably that the prefrontal cortex is not involved in conscious processing. There is enormous connectivity between the prefrontal cortex and other regions.
Cortical Neuropercolation (CNP)
Robert explains his Neuropercolation Theory, which describes the cortical phase transitions in the neuropil, also known as Layer I. These phase transitions take place between a basal state, consisting of competing, local, fragmented components, and a state of high coherence across the hemisphere globally.
Bernie highlights Robert’s past work with the great neuroscientist Walter J. Freeman. He describes their findings, specifically the groundbreaking discovery that in Layer I of the cortex an all-or-none “phase change” occurs 10 times per second. During this phase change, the Layer I self-organizes, which is then followed by a chaotic disorganization, or a collapse. Both processes are important because self-organization freezes information and disorganization opens up the system for new information.
Layer I is different from the other layers of cortex, in that the dendritic branches connect to each other like the threads in a horizontal cloth that connect to each other. This is called a horizontal “feltwork”.
What does it mean that multiple gestalts emerge in the same conscious experience?
Metacognition: Using the Prefrontal Cortex to Think About Thinking
How can metacognition be defined? Robert explains that metacognition is the process of thinking about one’s thoughts. Bernie differentiates between conscious metacognition, or the conscious process of thinking about one’s thoughts, and unconscious metacognition, which include “self conscious” emotions such as shame and pride. Both conscious and unconscious metacognition can exist at the same time.
The Dynamical Connectome of Cortex
In closing, Bernie describes the work of Gustavo Deco and his colleagues in Spain, the most recent contributors to the Global Workspace “family” of theories. Deco et al. (2021) define a functional “rich club” of active cerebral nodes and connectivities that may function as a dynamic global workspace, one that is not rigidly tied to a single anatomical region of cortex. There may be other ways to identify global workspace dynamics, but this appears to be a well-specified candidate.
An arbitrary division between the prefrontal cortex and other brain regions can be misleading. The cortex is the leading edge of life adaptation to all the environmental events we encounter. The cortex is also the most highly interconnected organ of the brain.
Deco, G., Vidaurre, D. & Kringelbach, M.L. Revisiting the global workspace orchestrating the hierarchical organization of the human brain. Nat Hum Behav 5, 497–511 (2021). https://doi.org/10.1038/
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Talking Points
0:00 – Intro
4:04 – Divisions between PfC and other neuronal regions tend to be misleading.
5:57 – Global Workspace Theory: An Overview
10:23 – The Role of Metaphors in Science
15:37 – Consciousness is the Dynamic Core of the Brain.
21:44 – Unifying Principles of the Global Workspace “Family” of Theories
30:59 – What is “Binding” and “Broadcasting” in the Brain?
34:39 – What did Raccah et al. (2021) Get Wrong about GWT?
43:22 – What is Neuropercolation Theory?
58:12 – Conscious and Unconscious Metacognition
01:07:07 – The Dynamical Connectome of Cortex
01:12:01 – Functional Rich Clubs (FRICs) by Deco et al. (2021): Part of GW “Family”
01:17:30 – Final Thoughts
Bios
Bernard J. Baars: a former Senior Fellow in Theoretical Neurobiology at The Neurosciences Institute in La Jolla, CA, Bernie is best known as the originator of the global workspace theory and global workspace dynamics, a theory of human cognitive architecture, the cortex and consciousness. Bernie’s many acclaimed books include A Cognitive Theory of Consciousness; The Cognitive Revolution in Psychology; In the Theater of Consciousness: The Workspace of the Mind; Fundamentals of Cognitive Neuroscience. Winner of the 2019 Hermann von Helmholtz Life Contribution Award by the International Neural Network Society, which recognizes work in perception proven to be paradigm changing and long-lasting.
Robert Kozma, PhD:
Robert Kozma is the Professor & Director of the Center for Large-Scale Integrated Optimization and Networks (CLION) at the FedEx Institute of Technology, and Professor of Mathematics in the Department of Mathematical Sciences at the University of Memphis. Robert is Editor-In-Chief of IEEE Transactions on Systems, Man, and Cybernetics and past President of INNS, the Int’l Neural Networks Society.
Professor Kozma focuses on developing novel artificial intelligent systems motivated by the operation of brains. He conducts research on neural networks, machine learning, large-scale random graphs and networks, computational neuroscience, brain-computer interaction, among other areas. Kozma received his PhD in physics in 1992 from the Delft University of Technology and joined CICS as a visiting professor in 2016. Previous academic positions in the US include University of Memphis and University of California at Berkeley.
Links & Publications
https://www.memphis.edu/clion/
https://ieeexplore.ieee.org/author/37284339400
PubMed Publications for Robert Kozma
https://pubmed.ncbi.nlm.nih.gov/?term=Kozma%2C%20Robert
Neuropercolation Theory (PDF)
https://escholarship.org/content/qt2qn4778j/qt2qn4778j.pdf
Link to paper by Deco et al. (2021)
https://www.nature.com/articles/s41562-020-01003-6
Global Workspace Theory (GWT) began with this question: “How does a serial, integrated and very limited stream of consciousness emerge from a nervous system that is mostly unconscious, distributed, parallel and of enormous capacity?”
GWT is a widely used framework for the role of conscious and unconscious experiences in the functioning of the brain, as Baars first suggested in 1983.
A set of explicit assumptions that can be tested, as many of them have been. These updated works by Bernie Baars, the recipient of the 2019 Hermann von Helmholtz Life Contribution Award by International Neural Network Society form a coherent effort to organize a large and growing body of scientific evidence about conscious brains.
