Temporal order recognition memory: behavioral characterization and ERK1/2 involvement in learning

D'HERS, SANTIAGO; OJEA RAMOS, SANTIAGO; GUIDOBONO, SANTIAGO; ROMANO, ARTURO; FELD, MARIANA

Congreso; XXXVII Reunion anual de la SAN; 2022

Recognition memory depends on identification and judgment of the prior occurrence of events. It is a very sensitive declarative memory and the use of the temporal component of memory might have a relevant predictive power for early diagnosis of Alzheimer’s disease (AD). Evidence suggests that medial prefrontal cortex (PFC) and hippocampus (HIP) are important for this memory. Here, we characterized a temporal order recognition memory (TORM) induced by a two-session protocol in mice. Retention was assessed at 3 or 24 h in males and females. We also initiated the study of molecular and cellular bases underlying learning of this task. Particularly, we studied ERK1/2 (extracellular-signal regulated kinase 1/2) activation, which was initially associated to cell division and differentiation and was later shown to play a very important role in learning and memory processes. However, its role in temporal memories has not been elucidated yet. We found no significant differences in performance between sexes at 2 months of age, but 3 month-old males expressed less total exploration and better discrimination indexes than females in a 24 h test. Finally, although results are preliminary, we found clear tendencies in TORM-induced cytosolic ERK2 activation kinetics in both structures. These promising results lead to further study the behavioral effects of local pharmacological intervention of the pathway in order to understand its role in the formation of temporary memories.