Book review of JeanPierre Changeux

JeanPierre Changeux:
NEURONAL MAN (Pantheon, 1985)

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Changeux is one of the brain scientists who maintain that the mental and the neural are simply two aspects of the same physical state.
From neuroanatomy Changeux derives a view of the complexity of the brain: the evidence for specific localization of particular functions always comes with evidence for diffuse control and interaction of parts.
The human brain is priviliged by the (relatively recent) development of the neocortex. The human brain contains representations of the world in its cortex, is capable of building new mental representations and is capable of using them for computations. A mental object corresponds to the activity of a population of neurons.
Changeaus notes that at the level of communication between nerves nothing distinguishes the brain from the peripheral nervous system, or, for that matter, from any other animal.
Changeux proposes a "neo-darwinian" theory for the development of the set of nerve connections that underlie memories and perceptions. The nervous system makes very large numbers of random multiple connections. External stimuli cause differential elimination of some connections. Phenotypic variability is the result of experience.
His theory of "epigenesis by selective stabilization of synapses" stems from a number of observations: the main organizational features of the nervous system are determined by a set of genes; phenotypic variability increases in organisms with the increase in brain complexity; during development connections are created and destroyed in large numbers; neurons communicate even at very early stages of development.
The theory explains the nonlinearity between the complexity of the genome and that of brain complexity. 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.