Tag Archives: analog

The John paper 3

 

This is the third post about this paper, E. Roy John; The neurophysics of consciousness; Brain Research Reviews, 39, 2002 pp 1-28. One of the things that stands out in the paper is the idea of a ‘field’ theory of consciousness. John takes time to look at a Quantum theory and the Tononi-Edelman theory to illustrate other ways of looking at non-local brain activity.

Other contemporary theorists have recognized the need to focus upon the system rather than its individual elements. An electrical field must be generated by synchronized oscillations and the resulting inhomogeneity of ionic charge distribution within the space of the brain. Llinas and his colleagues suggest that consciousness is inherent in a synchronized state of the brain, modulated by sensory inputs. Libet proposed that subjective experience may arise from a field emerging from neural synchrony and coherence, not reducible to any known physical process. Squires suggested that consciousness may be a primitive ingredient of the world, i.e. not reducible to other properties in physics, and includes the qualia of experience. Others have proposed that consciousness arises within a dynamic core, a persisting reverberation of interactions in an ensemble of neurons which maintains unity even if its composition is constantly changing. ”

He leans towards the Tononi-Edelman picture and the emergence of consciousness from global brain activity. “This paper illustrates the increasingly recognized need to consider global as well as local processes in the search for better explanations of how the brain accomplishes the transformation from synchronous and distributed neuronal discharges to seamless global subjective awareness.

John says that consciousness is analog in nature (or a combination of digital local activity and analog non-local activity). What exactly is meant by analog mechanisms? An analog is a mimic of the system you want to solve or understand. The elements and the relations between elements are all represented in the analog. Analogs are physical copies. One of the most famous analogs is an electrical circuit and a hydraulic circuit. There are pairs of elements and the same forms of equation describing behavior. Voltage is like the head of pressure and so on. In teaching it is used both ways as some things are easier to comprehend in water and some in electrical current. The same elements and equations can be used in a mechanical analog or a pneumatic one. Analogs can be used to make calculations. The analog is a real physical system with real behavior and its values are continuous rather than digital. One of the great advantages of analog computers (electrical analogs of other systems built anew on a patch board for each problem or calculation) was that they did iterative problems in a flash. Digital computers soon were able to do iteration very quickly and patch boards became a thing of the past. The brain, however, is not a lightening fast thing. If it was doing iteration it would take significant time.

The brain is faced with a large number of semi-independent pieces of information from the senses, the memory, previous predictions, motor programs, knowledge of the world, on-going tasks/goals etc. These pieces of information are held by a huge number of cells. These cells have contact with many others and that contact is specific to each pair of cells. Step by step algorithms are not going to make a moment of perception out of that mass in less than several minutes, maybe much longer, because much of the work is iterative. But that mass using massive parallel and overlapping feedback loops can make an analog of the world in that moment in ‘a flash’. Signals may fly in all directions but the whole thing will only be stable in a few best-fit-scenarios and once in a stable point, will stay there. Presto, a global perception, including in its scope all the constraints and also not losing or degrading the original pieces of information (the qualia and feelings).

But then there is the ‘almighty leap’ – how is this perception shared and how are we made consciously aware of it. The ‘hard problem’ is not the qualia but the awareness. John skips over this. His explanation in its shortest form is:

CONSCIOUSNESS EMERGES FROM RESONATING ORGANIZED ENERGY: Simultaneously, the global perception is projected to the consciousness system. – subjective awareness of the percept emerges as a property of an electrical field resonating throughout the consciousness system.”

Now, many neuroscientists are convinced that the ‘unitary self’ is an illusion created from many selves such as an internal sense self, a motor self, an external sense self and so on. And why do we have an illusionary unitary self – well, to be aware of consciousness, to have subjective awareness. But if the subjective self is an illusion, why can’t the awareness by an illusion too.

After all, now every cell in the created analog is, if effect, in possession of the only part of the analog that it can possess. You could say it was ‘aware’ of the analog from its point of view. There was nothing about the new perceptual moment that it needs to be told.

But if self and awareness are illusions. What is this illusion in aid of? I would guess that it is needed for a useful memory. One perceptual moment has to be tied to another to construct a narrative, a biographical narrative so that there can be a longer term continuity in our thought and action.

That is the end of my posting on the John paper.