[Local changes in the rabbit brain cortex redox potential accompanying the formation of a conditioned defensive reflex].

The brain E is determined by ratio in rate of processes occuring in two energy compartments--in glycolysis (the more ancient one in evolution) in which glucose is splitted whithout oxygen utilization, and in oxidative metabolism which is younger in evolution than glycolysis and more effective than glycolysis. In the present investigation, the brain cortex E changes were recorded with implanted platinum electrodes. CDR was established by combination of light and electric shock applied to the left ear. It has been found that the combinations started to be accompanied by the E shift after the first 5-20 combinations. The E shifts were widely generalized over the cortex, and both increasing and decreasing E were well expressed within 50-200 combinations. As the number of combination increased, the increases in E were gradually replaced by the decreases in E. This dynamic in the balance of the major sources of the brain energy supply during the formation of CDR demonstrates, in our opinion, that subcellular structures or complexes of cells which appeared at the same stages of evolution as the compartment of oxidative metabolism make a significant contribution to the CDR acquisition when memory traces are created, while brain function during realization of well consolidated CDR are supported mainly by glycolysis.