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Version 4.0: 2024-04-01 Redone to focus on LeDoux's Mental Model of Consciousness (V3.1)

C is for Consciousness

The latter three realms are also referred to as anoetic (neurobiological, model-free), noetic (cognitive, model-based, pre-conscious), and autonoetic (conscious, the ability to mentally model one's self in relation to time).

On the right is the key image that shows how consciousness works as flows of Mentalese, a narrative stream of bundles of abstract concepts that flows thru the brain. The box labeled Mental Model 2 is the autonoetic process that represents consciousness. It distributes its narrative to take conscious action and to generate language that is our inner monologue, or speech or writing. It also modifies Mental Model 1 based on conscious insights and understanding of what it going on in Reality.

Mental Model 1, the pre-conscious mental model, is our autopilot, or the Elephant in the Elephant and the Rider metaphor. It is perfectly capable of running the ship of our existence. It can drive you home without having to bother you with the routine traffic lights and such. The arrows at the bottom right represent the feedback loops with the various anoetic processes, such as the senses, our body state, subconscious goals, etc. See Full Figure 26.2 Image. There is more about LeDoux's Theory in my Notes on the 4 Realms.

The rest of this page gives a brief note and pointers for the key concepts needed to understand consciousness, from my perspective.

The Physical elements ( of the brain ) are referred to as tissue scientifically. Flesh: simple muscles are miraculous and the brain is unfathomably complex. Key concepts:
1 ) Preconditions: Arousal and Vigilance,
2 ) Cortico-Thalamic Complex
3 ) Gray Matter and White Matter
4 ) Brain Regions,  
5 ) Cortical Columns,  

The Information Concepts are:
6 ) Mental Models and Simulation
7 ) Predictive Coding & Processing
8 ) Coalitions of Neurons, Global Ignition, Unity
9 ) Large Scale Brain Networks,  
10 ) Levels of Consciousness: anoetic, noetic, autonoetic,
11 ) Mentalese,

Other good concepts for understanding how consciousness works,
A ) Spatiotopic Activity Maps,
B ) Unitary Nature of Consciousness and its Limited Capacity,
C ) Embodied Cognition & Self

Barrett's model of consciousness (experiencing Reality): "Your experiences are not a window into reality. Rather, your brain is wired to model your world, driven by what is relevant for your body budget (allostasis), and then you experience that model as Reality..."

See Dehaene: What is Consciousness Good For?

1. Preconditions: Arousal and Vigilance

Consciousness only happens when you are conscious. Arousal is the state of being awake as governed by the Reticular_Activating_System (RAS). Consciousness implies you can pay Attention. Vigilance is sustained concentrated attention.

Arousal Network Atlas

Feeling of Life, p.54 "The brainstem houses at least forty distinct groups of neurons in cellular assemblies named the reticular formation or ascending reticular activating system. Each population uses its own neurotransmitter, such as glutamate, acetylcholine, serotonin, noradrenaline, GABA, histamine, adenosine, and orexin, which modulates, either directly or indirectly, the excitability of cortex and other forebrain structures. Collectively, they access and control signals relating to the internal milieu: breathing, thermal regulation, REM and non-REM sleep, sleep—wake transitions, eye muscles, and the musculo-skeletal frame. Brainstem neurons enable consciousness by suffusing cortex with a cocktail of neuromodulatory substances, setting the stage on which mental life plays out. But do not confuse them with the actors that perform the play. The brainstem doesn't provide the content of any one experience. Patients with spared brainstem function but widespread cortical dysfunction typically remain in a behaviorally unresponsive state, without signs of consciousness of self or their environment."

From Wikipedia Arousal:
"There are many different neural systems involved in what is collectively known as the arousal system. Five major systems originating in the brainstem, with connections extending throughout the cortex, are based on the brain's neurotransmitters,   acetylcholine, norepinephrine, dopamine, histamine, and serotonin."

6. Cortico-Thalamic Complex

[Thru extensive loops and connection to the cortex, the thalamus coordinates] "Bayesian inference in the brain, as entailed by the Free Energy Principle (Friston, 2003). In this article, we will use spatial cognition, planning of movements, and risk-reward trade-off decisions as three examples to illustrate the role of the thalamus as a central blackboard, central in terms of its physical location and role in information processing."
From: The Thalamus as a Blackboard for Perception and Planning

GEEK Art: CorticoThalamic Animation and Introduction to CT animaiton

Cortico-Thalamic Resonance on Wikipedia

Thalamus, Greek for "chamber" on Wikipedia. Almost all sensory informaiton goes thru the Thalamus, with some aspect of smell have a more direct route. Each sense goes thru a perticular nucleus, with the visual information from the optic nerve going into the LGN and then thru the optic radiation to V1. There are no direct connections between the nuclei of the Thalamus.

The Global Neuronal Workspace (GW) is a functional hub of connections between all brain regions using a network of long distance axons that loop through the Thalamus. The dynamic capacity for binding and propagation of signals within the system allows for coalitions of neurons to connect different brain regions to form conscious percepts. Multiple coalitions exist at a pre-conscious level and compete for dominance. The succession of winning neural coalitions forms our stream of consciousness. It is also a theory of Consciousness that is not really incompatible with the one described here, IMHO.

Dehaene articulates the Global Neuronal Workspace. The most concise description is in the introduction to Chapter 5: p.161

The proposal is simple: consciousness is brain-wide information sharing. The human brain has developed efficient long-distance networks, particularly in the prefrontal cortex, to select relevant information and disseminate it throughout the brain. Consciousness is an evolved device that allows us to attend to a piece of information and keep it active within this broadcasting system. Once the information is conscious, it can be flexibly routed to other areas according to our current goals. Thus we can name it, evaluate it, memorize it, or use it to plan the future. Computer simulations of neural networks show that the global neuronal workspace hypothesis generates precisely the signatures that we see in experimental brain recordings. It can also explain why vast amounts of knowledge remain inaccessible to our consciousness.

Churchland has a concise description of Global Workspace Theory.

3) Gray Matter and White Matter

Gray matter is the neocortex. It is a 2D manifold, or sheets of thin layers of neurons and supporting glial cells. Most of the sheet has six layers, but some have 4 or fewer. The cortex should be thought of as a large (30cm+/-) pancake that is folded in on itself. The pinkish brain to the right shows how the folded pancake can fit in the skull. The big sections are called lobes, the second level of folding size is called a gyrus, as in the cingulate gyrus. The division between folds is called a gyrus, plural - gyri.

The gray matter is organized into patches, see cortical regions below and vertically, see cortical columns below. Each column has a long axon, which is a long branch of the nerve cell that transmits information to another set of neurons. Within the gray matter there are several types of neurons with the most well known being pyramid and mirror neurons.

Here is a drawing by Santiago Cajal [ CAH Hal ] of some pyramidal neurons. The cell bodies are the dark blobs, and dendrites are the branches expanding out to talk with other neurons. Dendrite is based on the Greek word for tree, as in rhododendron. Cajal drew this and may others illustrations just over 100 years ago. If I zoom in on these pyramid neurons, you can see Cajal's little 'a' for axon.

Cajal Pyramidal Neuron

Cerebral Cortex on WikiPedia

Cytoarchitecture of cerebral cortex is a fairly digestable resource for the different types and make up of the gray matter.

White matter consists of the long efferent (output) axons that are myelinated. Myelin is a white fatty material that forms a sheath around the axon to protect signal integrity. The myelin and axons are too small for us to scan at this time.

To the right is an MRI slice thru the brain showing Gray Matter & White Matter. The gray matter is where the brain regions are and the white matter is what connects the brain regions. In the upper right corner of the image is zoomed in a bit. In the lower right corner, I have exaggerated the gray matter and white matter. The gray matter is where all of the neuron cell bodies and dendrites are. We can create images of the pathways of the axons using Diffusion Tensor Imaging (DTI).

Forest Metaphor for Neocortex:   Imagine the neocortex is forest of tall oak trees. The canopy is 6 layers deep and the tree trunk is an axon that runs out of this column to spread its news. The leaves and branches are sharing information with all of the trees in the neighborhood. And some news is carried in from afar. The axon leaving the tree trunk does not split in the roots right away. It travels to some other region of the forest, or perhaps into central intelligence - the thalamus. If the efferent (axon leaving) is heading to another region of the forest, then by this metaphor, the roots would spring out of the ground and the roots would send out dendrites that would eventually meet the other trees leaves and branches at synapses.

DTI & fMRI

Beautiful Connectome - Artist Unknown

Images of the axon connections (white matter) between brain regions. The left is the first detailed map of connecitons, made of the visual cortext in 1991. More recent Beautiful imges from 2021

Felleman, D.J., Van Essen, D.C. (1991). Distributed Hierarchical Processing

Beautiful imges from 2021

Circular Rep/Human Cortical Networks Andrei Irimia, Micah C. Chambers, C. M. Torgerson, J D Van Horn

4. Brain Regions

There are 4 different ways we know about brain regions. FACT - Functional, Architecture, Connectivity, Topography. We can say what the functional areas are from brain lesions and fMRI. Architecture, or Cytoarchitecture is the structure of the 6 layers and the types of neurons in a region. Connectivity is where the wires run from this region. Topography is where it is physically in the brain.

In 1861, Paul Broca identified a lesion on a specific brain region destroyed a person's ability to speak, but left all other brain functions intact. That area is now known as Broca's area. Soon, Wernicke''s_area was identified. There are countless fascinating (and tragic) stories of Prosopagnosia, Motion_blindness, Blindsight to name a few.
, fMRI Viz, (more)

In 1909, Korbinian_Brodmann published his maps of cortical areas based on Cytoarchitecture, the physiological differences in the cell structure of different regions of the neocortex. more.

There are dozens of parcellation atlases. There are different methods to parcellate brain regions. How many parcels are there? There are probably a core set of 50-60 that everyone has. Some of the atlases go up to 360 regions. Sterling proposes 200 potential areas, but, not everyone has them all. Humans distributed skills to improve adaptability. How to think about and brain cartography

The largest area the V1, the primary visual cortex. wikipedia/List_of_regions_in_the_human_brain

Good paper: Network architecture of the long-distance pathways in the macaque brain (2010) by Dharmendra S. Modha and Raghavendra Singh. It shows the connections between 383 different brain regions. They use a Visualization technique called "bundling" that combines lines going in the same direction. Brain Cheat Sheet. Andrei Irimia did a similar visualization for Humans.

On Mar 15, 2024, at 12:19, Max Bennett wrotein response to this question:
Do you think the notion of specific brain regions has been oversold? Perhaps, the sea of columns does have regions but the blurry boundary regions take up more space than the regions?

"I think the answer is, as with many things in biology, a middle ground. Strict assignment of behavioral or computational functions to specific regions is perilous and unlikely to be accurate, given the messiness of evolution and the fact that behavioral skills and computations likely emerge from interplays between many regions. But I don't think this means there is no fruit to bear when it comes to trying to reverse engineer the algorithms being implemented by various regions, and how these computations play a role in the emergent behaviors. There are clearly visual, auditory, somatosensory, and motor dominant neocortical areas. But the "function" they are performing is up for debate."
 

5. Cortical Columns

I first heard about cortical columns and the Cortical Algorithm, which is essentially desribes predictivie coding. Each column is about 0.5mm square. Over 100,000 (100K) columns in the 30mm pancake that is the neocrtex.

WikiPedia: Cortical Column
From: Numenta article

Vernon Mountcastle proposed that the neocortex is organized into many structurally similar cortical columns that perform the same computation at every region, and every level of the hierarchy. We have around 150,000 cortical columns in our brain. Cortical columns span from the top to bottom of the neocortex and are much larger.

Mini-columns are small groups of pyramidal neurons that exist within one layer of each cortical column. The input layer of each cortical column are arranged in mini-columns. In our simulations, there are typically 150-250 mini-columns per cortical column, with 16 cells per mini-column.

Very dense, very intensely detailed description of a cortical column: An Attempt at a Unified Theory of the Neocortical Microcircuit in Sensory Cortex side view of 5 cortical columns, aka, prediction units.

To the right is an image of five cortical columns processing rat whicskers is from Beyond the Cortical Column - Structural Organization Principles in Rat Vibrissal Cortex, by Marcel Oberlaender, Rajeev Narayanan, Robert Egger, Hanno Meyer, Lothar Baltruschat, Vincent Dercksen, Randy Bruno, Christian de Kock, and Bert Sakmann in Neuroinformatics 2012. Permission to Use. A very similar image of the same dataset is used in this paper Generation of dense statistical connectomes from sparse morphological data.

What is Neurorepresentationalism (Pennartz) Fig. 3. Functional organization of different levels of representation in the construction of conscious experience.

LeDoux posits two mental models as the basis of consciousness. cognition [is] the capacity to construct models of the world and use these in thinking, planning, ...”

7. Predictive Coding & Processing

Here is a Gentle Introduction to Predictive Coding presented as a 'lay service' at First Parish.

There are four 'predictive processing theories': predictive coding, hierarchical temporal memory (HTM), bayesian inference, and Adaptive Resonance Theory (ART).

Predictive Coding: a Theoretical and Experimental Review 2021 - Beren Millidge, Anil Seth, Christopher L Buckley - https://arxiv.org/abs/2107.12979

"There remains an intrinsic tension, however, between these two perspectives on precision in the literature. The first interprets precision as a bottom-up ‘objective’ measure of the intrinsic variance in the sensory data and then, deeper in the hierarchy, the intrinsic variance of activities at later processing stages. This contrasts strongly with views of precision as serving a general purpose adaptive modulatory function as in attention."

Good source with intro: github.com/BerenMillidge/Predictive_Coding_Papers

The Quest for Consciousness: 3) Conscious precepts are the results of a single winning coalition of neurons

Hex Brain - Consciousness is made of Coalitions which are Connected Columns Conspiring

The image is actually from a pigeon. I picked in in 2014 when there was less choice, but, I still like it, even tho, it is not really a coalition, but the full connectome. Here is the paper.

Large-scale network organization in the avian forebrain: a connectivity matrix and theoretical analysis

Dominant coalitions are fleeting . . .

The Quest for Consciousness: 7) Perceptual awareness may be a series of snapshots with motion "painted on". Each snap lasts 20-200 milliseconds (ms) (it takes 250 ms to "see" something) Loops within the CT complex synchronize. Fire together; wire together.

Using MEG, we can tell that two brain regions are synchronized. The image to right is from Kirschner 2012 Differential synchronization in default and task-specific networks of the human brain.

Baars 2013: Since “binding” and “broadcasting” involve adaptive resonance, the distinctive type of signaling in the C-T core, dGW suggests “binding resonance” to define the winner-take-all gestalt that becomes conscious and “broadcasting resonance” to propagate the winning gestalt to receiving networks.

Koch 10 Assumption (2004) 9) synchrony of action potentials discharge in the 30-60Hz range may help in forming nascent coalitions. Firing in the 4-12 Hz band may be part of snapshot processing.

Dehaene p.135 - "The bestiary of brain oscillations includes the alpha band (8 to 13 hertz), the beta band (13 to 30 hertz), and the gamma band (30 hertz and higher) [jch - hertz is per second. 8 hertz means a pulse every 1/8 second]"

Does resonance synchronize microstates? 100ms is 1/100th of a second.
Dynamic Global Workspace - . . "evidence for stable microstates in the EEG for both the rabbit and humans, exhibiting rapidly changing phase after ∼100–200 ms, the rate of theta oscillations (Freeman, 2007). Other laboratories, using quite different methods, have also reported momentarily stable, content-sensitive microstates. The current theory suggests that microstates represent binding and broadcasting equilibria involving dynamic coalitions of adaptively resonant populations of neurons. This view seems quite compatible with sophisticated theoretical work by Freeman and Kozma. Crick and Koch (2005) suggested the term "coalitions" for this general concept."
Koch's 10 predictions: 7) Perceptual awareness may be a series of snapshots with motion "painted on". Each snap lasts 20-200 milliseconds (ms) (it takes 250 ms to "see" something)

Wikipedia: Neural Oscillation, Neural Binding.

9. Large Scale Brain Networks

The image on the right shows the six networks that commonly identified. This from Large-scale brain networks... by Timothy F. Boerger et al. The six are the:
- Default Mode Network for when you are not focussed on the world, for example, day dreaming and self reference.
- Salience helps switch networks. Only one network is active at one time.
- More common networks: Attention, Visual and [Cognitive] Control. Note that these vary from person to person and different brain regions may participate in multiple networks.

Novelty and Global Ignition The subconscious deals nicely with the routine. Novelty ignites the global workspace that hijacks the rider.

Dehaene uses the term Signatures of Consciousness, an upgrade from correlates of consciousness found in Christof Koch's The Quest for Consciousness. I would not say these are really signatures of consciousness, but rather signatures that new stimuli have entered consciousness - have made it into the Global Workspace. We retain whatever is conscious without the constant refresh of these signatures. Here are the . . .

p. 159 - "four reliable signatures of consciousness - physiological markers that index whether the participant experienced a conscious percept.
First, a conscious stimulus causes an intense neuronal activation that leads to a sudden ignition of parietal and prefrontal circuits.
Second, in the EEG, conscious access is accompanied by a slow wave called the P3 wave, which emerges as late as one-third of a second after the stimulus.
Third, conscious ignition also triggers a late and sudden burst of high-frequency oscillations.
Finally, many regions exchange bidirectional and synchronized messages over long distances in the cortex, thus forming a global brain web."

An avalanche is also used as a metaphor for ignition. The subliminal rumble of neural activity is almost identical to the supraliminal. Just a little bit strong stimulus triggers and avalanche that gets a new precept into the Global Workspace.

Graziano's Attention Schema Theory in which the Attention Sceme is an internal mental model of own own attention, in that we are aware of being aware.

---

A ) Spatiotopic Activity Maps

Being awake means eyes open and vision flooding our awareness. We have 20-40 maps that are copies of what we are looking at with different bits of information, such as color, motion, object identification, etc. These are overlapped to compose a richly detailed mental model of what we are seeing. Above are 3 maps being and how they are arranged conceptually. The

In The Quest for Consciousness, Christof Koch uses the example of a red Ferrari zooming past to discuss the "binding problem". There are Multiple Retinotopic Maps of the Visual Field

This chapter from the Webvision Book, Psychophysics of Vision, by Michael Kalloniatis and Charles Luuhas, is a great overview of the visual system.

Collin Ware has a wonderful simple description of the various parts of the visual cortex and how they can be exploited. And Wikipedia:   Visual_space,   Visual_cortex

The the right is an image of the optic nerve, the Optic_chiasm, and, perhaps the LGN. This image is the RGBA dataset from the Visible Human project being rendered on a VP1000, aka VolumePro 1000.

B ) Unitary Nature / Limited Capacity of Consciousness

Only one coalition is dominant at any one point, but, coalitions may cycle.

Patricia Churchland Global Workspace Theory:
3) consciousness has limited capacity. Only 1 conversation, no long division while spotting of eddies.
. . . "multitasking, we are probably shifting attention back and forth between two or possibly three tasks, each of which is familiar and which we can perform with minor vigilance"]

From Feinberg & Mallatt, Consciousness Demystified 2018,

p.110   Conscious unity at the higher level of the special features is directly linked to reciprocal neural interactions that bind coded sets of sensory information together into a unified image or affect (top of plate 10). However, down at the more basic levels, all physiological life processes are integrated and unified to achieve homeostasis, and the reflexes are genetically prewired to create linked programs that effect unified actions. In short, the unity and integration that result from the special features (box 6.3) stem from the unified systemic features of life and the reflexes at the lower levels. Again, we have derived a gap feature at the top of plate 10 ("unity") from the physical features lower down in the figure.

The Frontal Pole switches between trains of thought, only letting one thru consciousness at a time. See LeDoux

The Unbearable Slowness of Being documents how slow our conscious thought process is. The claim is 10 bits per second, but 'bit' is a little fuzzy. A bit can be a thing, sort of like our ability to hold 7+/-2 seven plus or minus two things in mind. This corresponds

Seth's Self

There is the bodily self, which is the experience of being a body and of having a particular body. There is the perspectival self, which is the experience of perceiving the world from a particular first-person point of view. The volitional self involves experiences of intention and of agency — of urges to do this or that, and of being the causes of things that happen. At higher levels, we encounter narrative and social selves.

Richard Schwartz's Parts Therapy has the Self as an organizing principle. The self is totally calm and has ample untapped energy. The official name of Parts Therapy is IFS, Internal Family Systems, which makes sense from how the model got articulated.

2024-03-29 (jch) 2024-07-19 jch.com/notes/C <> jch