Reading the structure of brains

Abstract

It is a fashionable philosophical tenet to consider Darwinian evolution as a process which incorporates knowledge into brains. We ask ourselves: can this knowledge about the world be recognised in the structure of brains? The present article gives a partial answer to this. Mechanisms of information handling and storage may well be related to the impressive major cortices of the vertebrate brain, the cerebral and the cerebellar cortices. The structure of the first fits the idea of an associative memory while the second strongly suggests computation of movement in terms of velocities. In some insect brains the mechanisms of visual perception can be related to detailed neuroanatomical structure, and one such network incorporates knowledge about the optics of a camera-type eye. Another one provides the wiring that would be expected in a set of velocity detectors using the principle of cross-correlation of neighbouring inputs.

Knowledge acquired during a lifetime is also laid down in brains but the search for the ‘engram’ in the structure of brains has not yet been very successful.