A Rough Sketch of a Neurobiological Mechanism of Consciousness

I envision conscious states as being represented in the brain as local, transient patterns of neural activation linked together through a binding mechanism such as that proposed by Crick and Koch, or Gamma Wave Theory. At any instant in time, then, there is a specific subset of neurons firing in a brain that corresponds in some way to the current mental activity of the organism. For this picture, I adapt Damasio’s Convergence-Divergence Zone hypothesis, which states that across networks of brain regions, there exist highly connective nodes that record co-occurrent inputs, and activate a specific pattern of outputs. In doing so, by later activation of those outputs in the form of a memory, the original input pattern could be re-induced by Hebbian-type mechanisms. Since CDZs are highly interconnected, the evolution of a conscious state over time may be thought of as one pattern of neural activity systematically inducing another one, which induces another, and another, ad infinitum. If you are familiar with semantic networks, the idea is of some use in fully realising this proposal. In such networks, activation of one node (corresponding to, say, the idea of a dog) facilitates the activation of closely connected nodes (in this example, four-legged animals, or barking). My idea for conscious states over time corresponds very closely to this, except that it is not activation of individual nodes that matters, but activation of discrete patterns of nodes. Each activated node within this greater pattern can bring related nodes online, which depending on the strength and co-occurrence of activation, may induce another coherent pattern of activation through networks of CDZs.

I’ll continue this later.

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