Memory grows

Summary

The thesis is reaffirmed that form memory (recognition) resides in the morphology of neuronal arborescences, the latter constituting physiological counterparts of local phase portraits of the infinitesimal transformation groups involved. At birth the brain comes equipped with essentially its full complement of neurons. These are initially in a very primitive, almost neuroblast form, but subsequently rapidly proliferate and branch, thus keeping pace with the growth of memory and learning. The Neuron Doctrine is equivalent to the assertion that the neuron constitutes the infinitesimal generator of our perceptions and cognitions. Memory thus consists, in the present view, simply of invariant recognition under time changes. The usual mathematical structure governing invariance in the presence of an infinitesimal operator, namely, Lie transformation groups, together with their prolongations to establish higher differential invariants, then indicates how the engrain is laid down. Learning takes place via differential refinements of already existing neuropsychological invariances, and is embodied in growth of the neuronal arborescence. Empirical support for this hypothesis is discussed: Ribot's law of psychological regression, the characteristics of short-term memory consolidation, agreement between neuron morphology and local phase portrait, neuronal packing density, and persistence of memory through topological lesions. The view advanced here is in no essential conflict with the currently fashionable idea of “memory molecules”. The generation of such macromolecules is incidental to the neuroplasmic flow process, which acts to extend the neuronal arborescence in the presence of a stimulus.