Neurochemical Changes in Brains of Albino Rats Resulting from Avoidance Learning

Abstract

To observe the effects of avoidance training on the brain chemistry of trained rats, 36 Wistar albino rats, 60—75 days old, were run in an automated straight-runway maze. 12 Ss received limited avoidance training followed immediately by extinction training for the avoidance response. 12 other Ss received limited avoidance training only, and 12 is acted as non-trained controls. Following training, each S's brain was removed and sectioned into three gross anatomical parts: cerebrum, brain stem, and cerebellum. Chemical analyses for RNA, protein, and total nitrogen were performed on each brain section for each animal. Significant increases in cerebrum, brain stem, and cerebellum RNA were found for both trained groups. Such differences in RNA were strongly present in the brain stem and cerebrum but were nonsignificant for the cerebellum. Brain protein showed significant increases as a result of the interaction of cerebellum with avoidance training. Total nitrogen levels were unaltered. Two significant correlations obtained between neurochemistry and behavior, a zero-order correlation between brain-stem RNA and extinction behavior and a multiple correlation among brain-stem RNA, cerebral protein, and extinction behavior.