The neurochemical basis of learning and neurocomputation: the redox theory

This paper presents a new theory of the biochemical basis of learning and neurocomputation. It has now been determined that excitatory synapses on dendritic spines in the brain are continually being formed and removed. This requires a neurochemical mechanism. There is evidence to suggest that the redox state of the glutamate synapse plays an important role in determining the growth;th or deletion of that synapse. This redox state is controlled by the balance between the pro-oxidants hydrogen peroxide and the nitric acid radical, and the antioxidants ascorbate, carnosine, the nitrosium ion and catecholamines. Key enzymes involved are prostaglandin H synthase and nitric acid synthase. Mediation of signals of reinforcing stimuli by the catecholamines may be mediated in part by their antioxidant effect on glutamate synapses, Some experiments to test the theory are suggested. (C) 1999 Elsevier Science B.V. All rights reserved.