Behavioral tagging in spaced learning: contriburion of ERKs ½ kinases to spatial memory formation.

TINTORELLI, RAMIRO; BUDRIESI, PABLO; CORREA, JULIETA; VIOLA HAYDEE

lisboa

Congreso; International Society for Neurochemistry; 2023

International Society for Neurochemistry

The superiority of spaced over massed learning is anestablished fact in the formation of long-termmemories (LTM). Here we addressed the cellularprocesses and the temporal demands of thisphenomenon using a weak spatial object recognition(wSOR) training, which leads to a short-term memory(30 minutes post-training) but not to LTM (24 hourspost-training). We observed that two identical wSORtraining sessions promoted LTM formation in a spaced,but not in a massed, training protocol. The promotingeffect depended on neural activity and proteinsynthesis in the dorsal hippocampus. Based on the"behavioral tagging" hypothesis, which postulates thatlearning induces a neural tag that requires proteins toform LTM, we propose that retraining mainly retags thesites initially labeled by the prior training. Thus, whenweak, consecutive training sessions are experiencedwithin an appropriate spacing, the intracellularmechanisms triggered by each session would add,thereby reaching the threshold for protein synthesisrequired for memory consolidation. ERKs1/2 kinaseswere found to play a dual role in SOR-LTM formationafter spaced learning, inducing protein synthesis andsetting the SOR learning-tag. Western blot resultsshow that the dynamics of ERKs1/2 phosphorylationand activation correlates with the spatial trainingprotocol used.