PT - JOURNAL ARTICLE AU - Michaël Loureiro AU - Thibault Cholvin AU - Joëlle Lopez AU - Nicolas Merienne AU - Asma Latreche AU - Brigitte Cosquer AU - Karine Geiger AU - Christian Kelche AU - Jean-Christophe Cassel AU - Anne Pereira de Vasconcelos TI - The Ventral Midline Thalamus (Reuniens and Rhomboid Nuclei) Contributes to the Persistence of Spatial Memory in Rats AID - 10.1523/JNEUROSCI.0410-12.2012 DP - 2012 Jul 18 TA - The Journal of Neuroscience PG - 9947--9959 VI - 32 IP - 29 4099 - http://www.jneurosci.org/content/32/29/9947.short 4100 - http://www.jneurosci.org/content/32/29/9947.full SO - J. Neurosci.2012 Jul 18; 32 AB - The formation of enduring declarative-like memories engages a dialog between the hippocampus and the prefrontal cortex (PFC). Electrophysiological and neuroanatomical evidence for reciprocal connections with both of these structures makes the reuniens and rhomboid nuclei (ReRh) of the thalamus a major functional link between the PFC and hippocampus. Using immediate early gene imaging (c-Fos), fiber-sparing excitotoxic lesion, and reversible inactivation in rats, we provide evidence demonstrating a contribution of the ReRh to the persistence of a spatial memory. Intact rats trained in a Morris water maze showed increased c-Fos expression (vs home cage and visible platform groups: >500%) in the ReRh when tested in a probe trial at a 25 d delay, against no change at a 5 d delay; behavioral performance was comparable at both delays. In rats subjected to excitotoxic fiber-sparing NMDA lesions circumscribed to the ReRh, we found normal acquisition of the water-maze task (vs sham-operated controls) and normal probe trial performance at the 5 d delay, but there was no evidence for memory retrieval at the 25 d delay. In rats having learned the water-maze task, lidocaine-induced inactivation of the ReRh right before the probe trial did not alter memory retrieval tested at the 5 d or 25 d delay. Together, these data suggest an implication of the ReRh in the long-term consolidation of a spatial memory at the system level. These nuclei could then be a key structure contributing to the transformation of a new hippocampal-dependent spatial memory into a remote one also depending on cortical networks.