A Gateway between Recent and Remote Memory

(Lesburgueres et al., 2011). Neuronal networks in these regions are, in fact, selectively remodeled at remote time-points (Restivo et al., 2009). Moreover, the persistence of these lately occurring structural changes is necessary for the persistence of memory (Vetere et al., 2011a). Surprisingly, in contrast with the intuitive idea that the neocortex might exclusively be dedicated to the storage of remote memory traces, it has been recently shown that lesions to lateral entorhinal cortex disrupt both recent and remote memory (Morrissey et al., 2012). Because this region is intimately connected with the HPC and the mPFC (Jones and Witter, 2007; Kerr et al., 2007), it therefore provides a crucial anatomical link potentially involved in the transfer of information between the two regions. There is evidence that, during a training episode, HPC activity is dominated by theta oscillations. Immediately after, HPC neurons burst synchronously constituting sharp waves which can propagate to other structures. Indeed, mPFC neurons are active during the recall of remote memories and their neuronal firing became selective for the association formed during the learning episode (Takehara-Nishiuchi and McNaughton, 2008). Nevertheless, how these regions interact to stabilize a recently acquired information into a long lasting memory was still unclear. In their paper published last year in Frontiers in Behavioral Neuroscience, Takehara-Nishiuchi et al. (2012) highlight this question by analyzing theta synchronization between LEC and HPC, and between LEC and the mPFC, their idea being that initial encoding of memories might be supported by LEC-HPC synchronization, and remote memory recall by LEC-mPFC synchronization. According to this view, the LEC might be initially involved in (i) transmitting sensory information to the HPC A commentary on