Thanks to some comments from the Mike Smith on my previous post, I began thinking about a proposed evolution of consciousness. To be clear, this is entirely hypothetical and idealized. The actual evolution is probably a lot more complex than we can imagine. I regard this as a thought experiment that aims to identify the critical elements during the evolutionary process that created consciousness.
The diagrams are intended to represent processes or more correctly categories of processes. Anatomical structures may not match. While the diagrams are not supposed to map to anatomy, there is a rough correspondence between various anatomical structures and the categories of processes, especially in the more primitive organisms. As brains have become complex, the capabilities expressed by the processes become distributed throughout the brain. This allows not only more sophisticated processes (more neurons involved with a single function), but also redundancy and integration.
Note: The dotted olfactory line in the diagrams is a minor exception to rule that diagrams represent processes, not anatomy., It represent an anatomical fact that the olfactory system does not signal through the router/controller but is connected closely to the spacetime positioning system.
Organism-0
Organism-0 is essentially an organism without information about the external world. It would have a controller brain with information about internal states and influence over the internal organism.
Organism-1
In Organism-1, an ability to interact the environment is added. Information comes from the senses; a smart routing function is added to the controller that enables some nuance in motor system responses that may be relatively hard-wired.
Organism-2
In Organism-2, the router controller is augmented by additional processing between the sense information and motor response. The senses are enhanced by additional processing . A basic spatial positioning system is developed to control mobility. There may have been a nascent reward/warning system that is shown in the diagram as a dotted circle. Sophistication of the networks borders on consciousness.
Organism-3
In Organism-3, consciousness arises from adding:
Space and time positioning
More sophisticated sensory processing
Capacity for learning and memory
A more complete reward/warning system
These are the key elements of consciousness. The reward/warning system ties mentality to the biological organism. Learning and memory requires senses, spacetime positioning, and a reward/warning system as an arbitrator for judging the context and value of actions generated by the motor system. The requirements of complex navigation may been have the evolutionary force that combined these elements. Consider the classic lab test: a mouse finds its way through a maze with its senses, learns the path by storing spacetime stamped memories, and reaches the morsel of reward at the end of the trail.
Organism-4
Organism-4 is an advanced organism such as a mammal or human. Reasoning, problem-solving, and communication capabilities evolve on top of Organism-3.
Summary
Consciousness develops in organisms as an extension of the internal biological control mechanisms through the evolution of capabilities for interacting with the environment. Consciousness is always oriented internally. While we usually think the content of consciousness is a representation of the external world, in fact, all of the content of consciousness is representation of internal biological states. This can be seen from its evolution from the controller in Organism-0. Internal models mimic the external world, but the model is completely a representation of internal states.
In my last post, I discussed C-Prime – the most simple, hypothetical brain and nervous system that could support consciousness. However, after that post, I realized I’d forgotten two things: feeling and a diagram. The problem in the model was there is nothing to drive learning. There would have to be a reward and warning process that reflects the states of the internal organism to attach a signature to a memory. We know this from the entire behaviorist paradigm that links learning to reward and punishment. Here’s the diagram.
Circular processes are those participating in consciousness. Processes are not meant to reflect actual anatomy, but rather broad functional processes.
Random Speculations and Thoughts
While the processes are not meant to reflect anatomy, the conscious processes do reflect in general terms a limbic system with sensory input. The contact point in the internal organism would be the brainstem.
A system such as this could have evolved from a more primitive system that directly connected senses and motor systems by evolving more sophisticated processing between the two systems.
Minimal consciousness consists of linking sensory, internal body state, and spacetime information into memory. Memory and learning at two ways of looking at the same process.
Consciousness arose in the evolution of biological control mechanisms for systems with digestive tracts and is primarily a representation of internal states in an external world. Hence, the explanation for its subjectivity.
A recent paper takes on the extradimensional explanation for consciousness: From Black Holes Entropy to Consciousness: The Dimensions of the Brain Connectome. The author, Dr. Denis LE BIHAN, seems fairly legitimate with a number of papers and significant positions held over the years. The core idea of the paper is “consciousness can naturally emerge from this four-dimensional brain connectome when a fifth dimension is considered, in the same way that gravity emerges from a ‘flat’ four-dimensional quantum world, without gravitation, present at the boundaries of a five-dimensional spacetime”. Black holes and holograms enter the discussion as well the Kazua-Klein theory that ties electromagnetism to relativity through an extra dimension. The problem with approach, as I see it, is that it would seem for the theory to work as presented in the paper, we would need to see relativistic effects in a low mass and relatively slow brain. We don’t see that, so this seems improbable.
I still think there may be something to the hologram idea which goes back at least as far the as holonomic brain theory. I will write more about this in a future post.
Another new paper claims to have discovered that when cells in the visual cortex are activated a kind of negative of the firing pattern forms in the memory areas. This suggests that the conventional view that upper level cortical uses abstract neural code might be wrong and the mapping may be more geometric. It could suggest also that memory areas may contain a reasonably complete representation of information in the sense organs.
Speaking of memory, a study has found that ripples in the brain “facilitate neuronal coupling in a phase-dependent manner and can organize the firing in entire assemblies of neurons”. “Ripples are bursts of high-frequency oscillatory activity that have recently been shown to synchronize across the cortex and may play a role in coordinating neuronal firing”. The hippocampus figures prominently in the coupling.
These findings are consistent with cortical ripples contributing to memory consolidation and recall in humans. Specifically, ripple co-occurrence could facilitate the binding of different elements of memories that are represented in disparate cortical areas, the essence of hippocampus-dependent memory.
Ripples co-occur, and remarkably, phase-synchronize across all lobes and between both hemispheres, with little decrement, even at long distances
The hippocampus is an odd structure.It has primarily been associated with memory until recent discoveries have also suggested a role on mapping location in space through place cells.
Hippocampus is a complex brain structure embedded deep into temporal lobe. It has a major role in learning and memory. It is a plastic and vulnerable structure that gets damaged by a variety of stimuli. Studies have shown that it also gets affected in a variety of neurological and psychiatric disorders.
We have two of them, one on each side, that are located at ear level and near the middle from front to back of the brain. It is shaped oddly, sometimes described as looking like a seahorse. It may be incorrect, however, to think of the hippocampus alone. Simply because anatomists have identified an area doesn’t mean that the brain uses the area in isolation from nearby areas, so interpret what I saying from here on as applying to hippocampus and associated areas. The hippocampus with its low central location would be in prime location for communication with other functional areas of the brain. What’s more, its input paths are the same as its output paths which suggests two-way communication.
There is a lot of information at the Wikipedia on the theta wave and the hippocampus.The hippocampus generates some of the strongest EEG signals in the brain. That would indicate that during wakefulness it is an area of high activity and likely stronger EM fields. During wakefulness, it has a theta rhythm of 4-8 Hertz. It shows a different pattern during sleep with irregular patterns punctuated by periods of sharp spikes. Some believe the hippocampus is where short-term memory is stored and that at night during sleep the memory is moved to longer term storage elsewhere. The hippocampus is also maybe the only place in the brain where neurons can regenerate themselves. The hippocampus is directly connected to the olfactory system
The hippocampus is found in all vertebrates. Analogous structures, which are also connected to the olfactory system, also exist in arthropods and may be used for navigation by insects. It’s location in the brain and its wide appearance across the animal kingdom suggest an ancient origin. We could speculate its direct connection to the olfactory system could suggest that smell was the first sense.
Another fascinating paper that caught my attention: Consciousness as a Memory System. This paper is long but a relatively easy read. It is jammed with basic facts and observations about how the brain works. I would recommend it just for that. I am going to quote the entire abstract:
We suggest that there is confusion between why consciousness developed and what additional functions, through continued evolution, it has co-opted. Consider episodic memory. If we believe that episodic memory evolved solely to accurately represent past events, it seems like a terrible system—prone to forgetting and false memories. However, if we believe that episodic memory developed to flexibly and creatively combine and rearrange memories of prior events in order to plan for the future, then it is quite a good system. We argue that consciousness originally developed as part of the episodic memory system—quite likely the part needed to accomplish that flexible recombining of information. We posit further that consciousness was subsequently co-opted to produce other functions that are not directly relevant to memory per se, such as problem-solving, abstract thinking, and language. We suggest that this theory is compatible with many phenomena, such as the slow speed and the after-the-fact order of consciousness, that cannot be explained well by other theories. We believe that our theory may have profound implications for understanding intentional action and consciousness in general. Moreover, we suggest that episodic memory and its associated memory systems of sensory, working, and semantic memory as a whole ought to be considered together as the conscious memory system in that they, together, give rise to the phenomenon of consciousness. Lastly, we suggest that the cerebral cortex is the part of the brain that makes consciousness possible, and that every cortical region contributes to this conscious memory system.
If this theory is correct, the hippocampus and related areas could be directly at the center of where consciousness is taking place.It could be place where much of the binding happens and it may have reasonably accurate copies of consciousness from other parts of the brain that are communicated by ripples and traveling waves.
The hippocampus is usually the place to which various neurodegenerative disorders can be traced. These disorders include Alzheimer’s and dementia. The hippocampus in people with schizophrenia. have a smaller cell volume. A number of people, however, have had portions of their hippocampus and/or amygdala removed in an effort to abate epileptic seizures. Usually only selective portions are removed based upon determination of the origin of epilepsy. Some have reported visual defects as well as the expected memory problems. One of the more extensive removals was the case of Henry Molaison or H,M as he is sometimes referred in the literature. Although the removal is sometimes described as complete, it seems unclear exactly how much was removed. A study in 2014 found that up to half of the hippocampal tissue remained. H.M. showed a variety of impairments in spatial and visual processing, but most notably the loss of ability to form new memories. He could fill in crossword puzzles when the clue was based on knowledge prior to the procedure in 1953, but could recall nothing for what happened after the procedure. Clive Wearing is another patient who suffered severe damage to the hippocampal area due to encephalitis. His condition was even worse than H.M’s. He would fill his diary with repetitive statements with timestamps minutes noting nothing more than he is now totally awake. He couldn’t remember from minute to minute.In each of these cases, however, other parts of the brain remained and could compensate for the deficits from the hippocampus. That makes a good argument that the hippocampus is only part of a larger system that generates consciousness. The authors of the Consciousness as a Memory System write: “we believe that consciousness would not be normal in individuals with complete absence or complete dysfunction of the hippocampus and related structures since birth.”
It seems apparent that consciousness in humans is located in multiple brain areas since people can lose substantial portions of it and still behave as if conscious, albeit cognitively disabled. But was this always true? Where did consciousness reside in the first conscious organism on Earth?
Let’s imagine the prototypal conscious organism in a minimalist form. We’ll call it C-prime.
It can move in the water by flippers.
It has one sense – a sense of smell.
It can detect potential food with its sense of smell.
It can react to move towards the source of food with its flippers.
How would C-prime work?
To move successfully to the food source, C-prime might have evolved a primitive hippocampus-like structure connected to the olfactory organ that can map the environment on an internal grid. It has its representative self on the grid in relationship to the food source as revealed by the strength and direction of the scent. This serves to direct its movement in the water. It starts swimming towards the food source with the information in the grid controlling the flippers.
To fine tune the search, however, another thing could be added. As it moves towards the food, small currents buffet C-prime away from the original direction slightly to the right or left, up or down. The food source could also be moving. As this happens, the scent becomes stronger or weaker. The strength of the scent in the new direction would be new information that could be used to fine tune the movement, effectively triangulating the position. However, this requires one additional feature to the hippocampus-like structure. It has to keep a record of strengths over time so it can compare the current scent with the previous scent. In other words, it needs a memory. The odd fact that the hippocampus is involved with both spatial mapping and memory makes sense.
Broad Speculations 