Piero Scaruffi(Copyright © 2013 Piero Scaruffi | Legal restrictions )
These are excerpts and elaborations from my book "The Nature of Consciousness"
Consciousness As Self-Reference
The idea of some form of "self-referential feedback" (of some kind of loop inside the brain) is firmly rooted in modern space-based binding theories. Gerald Edelman's "reentrant maps" and Nicholas Humphrey's "sensory reverberating feedback loop" are variations on the same theme. The idea is that, somehow, the brain refers to itself, and this self-referentiality, somehow, unchains consciousness. Rather than "space-based", these theories tend to be "process-based", since they are not only looking for the place where the binding occurs but also for the way it occurs, and the process turns out to be much more important than the place.
According to Edelman, consciousness is a natural development of the ability to build perceptual categories (such as “blue”, “tall”, “bird”, “tree”, “book”), the process that we normally call generalization. The brain can do this because neurons get organized by experience in maps, each neural map dealing with a feature of perceptions (color, shape, etc.).
First of all, Edelman distinguishes between primary consciousness (imagery and sensations, basically being aware of things in the world) and higher-order consciousness (language and self-awareness).
For primary consciousness to appear a few requirements must be met. It takes a memory, and an active type of memory, that does not simply store new information but also continuously reorganizes (or “re-categorizes”) old information. Then it takes the ability to learn, but learning is not only memorizing, it is also a way to rank stimuli, to assign “value” to stimuli, to value one experience over another. A new value will typically result in a new behavior, and that is what learning is about. Then it takes the ability to make the distinction between the self from the rest of the world, i.e. a way to represent what is part of the organism and what is not. Then it takes a way to represent chronology, to order events in time. Finally, it takes a maze of “global reentrant pathways” (i.e., forms of neural transmission that let signals travel simultaneously in both directions) connecting all these anatomical structures. Primary consciousness arises from "reentrant loops" that interconnect "perceptual categorization" and "value-laden" memory ("instincts"). In general, cognitive functions emerge from reentrant processes.
Consciousness therefore arises from the interaction of two parts of the neural system that differ radically in their anatomical structure, evolution, organization and function: the one responsible for categorizing (external stimuli) and the other responsible for "instinctive" behavior (i.e., homeostatic control of behavior). Consciousness emerges as the product of an ongoing categorical comparison of the workings of those two kinds of nervous system.
From an evolutionary point of view, the milestone moment was when a link emerged between category and value, between those two different areas of the brain. That is when the basis for consciousness was laid.
A higher-level consciousness (being aware of itself), probably unique to humans, is possible if the brain is also capable of abstracting the relationship between the self and the non-self, and this can only happen through social interaction, and this leads naturally to the development of linguistic faculties. Edelman identifies the regions that are assigned to define self within a species (the amygdala, the hippocampus, the hypothalamus) and those that operate to define the non-self (the cortex, the thalamus and the cerebellum).
Note that, according to Edelman, concept-formation preceded language. Language was enabled by anatomical changes. What changed with the advent of language is that concepts became independent of time, i.e. permanent. And semantics preceded syntax: acquiring phonological capacities provided the means for linking the preexisting conceptual operations with the emerging lexical operations.
In Edelman's picture, consciousness is liberation from the present. Animals tend to live in the present, simply reacting to stimuli. Only conscious animals can think about the past and about the future.
As for the “place” where consciousness happens (its neural correlate), Edelman noted that consciousness is unified and a "whole", while nothing in the brain seems to be unified and a "whole": in fact, the brain is made of a multitude of regions that exhibit independent personalities. Consciousness must therefore be due to a global process that encompasses more than one region. He believes that the thalamocortical system originates such an activity: a massive, coherent (synchronized) activity by all regions of the brain, that transcends the individual activity of each region. Basically, consciousness is a process that happens throughout the brain, not manufactured in a specific region.
The location of consciousness is changing all the time, as different groups of interacting regions form and dissolve. At any moment in time, the “dynamic core” of primary consciousness is located in the interaction between the thalamus and the cortex. He does envision one particular region as being the permanent site of consciousness. In a sense, consciousness is the “process” not the “place”.
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