The Nature of Consciousness

Piero Scaruffi

(Copyright © 2013 Piero Scaruffi | Legal restrictions )
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These are excerpts and elaborations from my book "The Nature of Consciousness"

Reverberating Loops

What Edelman and Llinas have in common is the belief that higher mental functions originates from a process of loops that reverberate through the brain (in particular, between the thalamus and the cortex, the thalamus being the source of so many crucial signals and the cortex being the newer, more sophisticated part of the brain). Their theories differ in the specific mechanism that they use but they both focus on the fact that regions of the brain are connected in a bidirectional way and that they "resonate" in response to each other, they are somehow in synch.

There are other models that exploit the same paradigm.

The Chilean neurologist Francisco Varela has claimed that there is a primary consciousness common to all vertebrates. This primary consciousness is not self-awareness but merely experience of a unitary mental state. Varela thinks that it is due to a process of "phase locking":  brain regions resonate, their neurons firing in synchrony, and create a cell assembly that integrates many different neural events (perceptions, emotions, memory, etc). This coherent oscillation of neurons is primary consciousness.

The US physicist Erich Harth tried to explain consciousness by means of a process that relies on "positive" feedback.  Feedback can be negative or positive. Negative feedback is the familiar one, which has to do with stabilizing a process, in particular the input with the output of the process (e.g., thermostats and car engines). Positive feedback works in the opposite direction, at the edge of instability: the signal is amplified by itself, weakening the relationship between input and output.  Harth thinks that a loop of positive feedback spreads through different areas of the brain and provides "selective amplification”. The loop basically joins the thalamus and the cortex, so that both send outputs that are inputs to the other. When input from the thalamus is stronger, the external world prevails. When input from the cortex is dominant, cognition prevails.

 


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