Piero Scaruffi(Copyright © 2013 Piero Scaruffi | Legal restrictions )
These are excerpts and elaborations from my book "The Nature of Consciousness"
A Brain in Transition
There are slight variations on the idea that the brain is a dynamic system.
The French neurobiologist Jean-Pierre Changeux introduced the paradigm of "epigenesis by selective stabilization of synapses". In his model too the nervous system makes very large numbers of random multiple connections while, at the same time, external stimuli cause differential elimination of some connections (useful ones are retained, useless ones are eliminated). Phenotypic variability (differences among individual brains) is the result of experience. As he put it, “the Darwinism of synapses replaces the Darwinism of genes”.
Interestingly, he noticed that phenotypic variability increases with the increase in brain complexity (the simpler the brain of a species the more similar the brains of individual members of that species). The evolutionary advantage of the human species stems from the individual, epigenetic variability in the organization of neurons, which resulted in greater plasticity in adapting to the environment.
The US neurologist Dale Purves, for example, has shown how brain cells are in a perennial state of flux, creating and destroying synapses all the time. Neural activity caused by external stimuli is responsible for the continual growth of the brain, and for sculpting a unique brain anatomy in every individual based on the individual's experience.
The British neurologist Semir Zeki argues that perception and comprehension of the world occur simultaneously thanks to reentrant (reciprocal) connections between all the specialized areas of the cerebral cortex. The function of the sensory parts of the cortex is to categorize environmental stimuli. The brain copes with a continually changing environment by focusing on a few unchanging characteristics of objects out of the countless ever-changing bits of information that it receives from those objects. The brain cannot simply absorb information from the environment. It must process it to extract those constant features that represent the physical essence of objects. The brain is basically programmed to make itself as independent as possible from world changes.
Patterns And Brains
The US mathematician Ben Goertzel believes that thinking, like life, is a process of evolution by natural selection. In general, Goertzel believes that Darwinism must be supplemented with a theory based on self-organization of complex systems. An organism that, coupled with the other organisms in its environment, generates a large amount of emergent pattern is more likely to survive. Consequently, his model replaces Edelman's neural maps with hierarchical structures that generate emergent pattern. Then neural maps can be viewed as populations that are reproducing sexually and evolving by natural selection. Basically, brain regions are equivalent to ecosystems. And Stephen Jay Gould's punctuated equilibrium applies as well to the cognitive development of an individual.
Goertzel views minds as sets of patterns interested in recognizing, creating and executing patterns. A mind recognizes patterns in the world, matches them to patterns that are contained within itself, and then creates new patterns both in the world and within itself.
The US physicist Eric Baum argues that mind originates from an "Occam program", a program that stores only the information that is truly needed and in a minimal form. Baum argues that the brain is an unlikely candidate for such a program. The genome, on the other hand, is just that: a program. Baum thus views the genome as the software (or, better, the source code) and the brain as the hardware (or, better, the executable code) that implements his Occam program to deal with environmental patterns, translate them into minimal mind patterns and then enact them as efficient behavioral patterns. And evolution is the software engineer that wrote the program.
The US neurobiologist Walter Freeman pioneered neurodynamics when, aiming to explain the meaning of an electroencephalogram, he introduced the concept of "mass action", the "force" that large populations of neurons in the cortex generate by synchronizing their firing of action potentials. This "force" is responsible for bursts of cortical activity that resembles the vortices of tornadoes and hurricanes. Freeman thought that these "bursts" corresponded with the formation of percepts. Freeman viewed these bursts of neural activity as the moments in time when the brain binds sensory inputs with memories. Cortical neurons belong to "sets" whose internal behavior can be modeled as made of three components. Linear dynamic equations can express two of them: the oscillation in time and the oscillation in space. Alas, when one adds the third component (the massive interconnections and feedback mechanisms of the neurons), the result is a system of nonlinear partial differential equations in time and space (Freeman thought that the "chaos" generated by these equations is precisely what makes consciousness possible).
These scientists place different emphasis on "how" the mind decides to build patterns. Does it use a goal-oriented approach (makes predictions that are useful for its goals), does it use a genetic-oriented approach (makes predictions that match its genetic repertory), or does it use a computational approach (makes the predictions that reduce the complexity of the world)?
The implementation in the brain of this prediction machine is the link between neural processes and symbolic processing: neural processes ultimately constitute the vehicle to create and manipulate symbols.
Presumably, this function involves a massive use of some form of Hebbian learning, leading from disjointed instances to more and more organic and abstract representations.
Thus generalization and metaphorical thinking are the fundamental basis of cognition.
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