Two spaced training trials induce associative ERK-dependent long- term memory in Neohelice granulata.

OJEA RAMOS, SANTIAGO; ANDINA, MATÍAS; ROMANO, ARTURO; FELD, MARIANA

BEHAVIOURAL BRAIN RESEARCH

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2021 vol. 403

0166-4328

Memory formation depends upon several parametric training conditions. Among them, trial number and intertrialinterval (ITI) are key factors to induce long-term retention. However, it is still unclear how individualtraining trials contribute to mechanisms underlying memory formation and stabilization. Contextual conditioningin Neohelice granulata has traditionally elicited associative long-term memory (LTM) after 15 spaced (ITI= 3 min) trials. Here, we show that LTM in crabs can be induced after only two training trials by increasing theITI to 45 min (2t-LTM) and maintaining the same training duration as in traditional protocols. This newlyobserved LTM was preserved for at least 96 h, exhibiting protein synthesis dependence during consolidation andreconsolidation as well as context-specificity. Moreover, we demonstrate that 2t-LTM depends on inter-trial andpost-training ERK activation showing a faster phosphorylation after the second trial compared to the first one. Insummary, we present a new training protocol in crabs through a reduced number of trials showing associativefeatures similar to traditional spaced training. This novel protocol allows for intra-training manipulation and theassessment of individual trial contribution to LTM formation.