micro-RNAs modulate spatial memory in the hippocampus and in the ventral striatum in a region specific manner

MicroRNAs are endogenous, noncoding RNAs
crucial for the post-transcriptional regulation of gene expression.
Their role in spatial memory formation, however, is
poorly explored. In this study, we analyzed learning-induced
microRNA expression in the hippocampus and in the ventral
striatum. Among miRNAs specifically downregulated by spatial
training, we focused on the hippocampus-specific miR-
324-5p and the ventral striatum-specific miR-24. In vivo overexpression
of the two miRNAs demonstrated that miR-324-5p
is able to impair memory if administered in the hippocampus
but not in the ventral striatum, while the opposite is true for
miR-24. Overall, these findings demonstrate a causal relationship
between miRNA expression changes and spatial memory
formation. Furthermore, they provide support for a regional
dissociation in the post-transcriptional processes underlying
spatial memory in the two brain structures analyzed.