PHOSPHORYLATION CHANGES FOLLOWING WEAKLY REINFORCED LEARNING AND ACTH-INDUCED MEMORY CONSOLIDATION FOR A WEAK LEARNING-EXPERIENCE

The formation of a protein synthesis-dependent long-term memory stage in day-old chicks trained on a passive discriminated avoidance task ha s been shown to occur only with an adequate level of reinforcement, an d is preceded by a significant change in the phosphorylation state of the forebrain synaptosomal membrane protein GAP43 protein. In the pres ent study, it is shown that weakly reinforced training did not lead to formation of a long-term memory stage or to any change in phosphate i ncorporation into forebrain P2M protein bands. However, administration of ACTH immediately posttraining led to both the formation of the lon g-term memory stage and a preceding significant increase in the phosph orylation of GAP43. These findings are consistent with the view that a reinforcement-dependent neurohormone-mediated change to the phosphory lation of this synaptosomal membrane protein may be implicated in the triggering of long-term memory consolidation.