Recent data reveal that the thalamic nucleus reuniens (RE) has a critical role in the extinction of conditioned fear. Muscimol (MUS) infusions into the RE impair within-session extinction of conditioned freezing and result in poor long-term extinction memories in rats. Although this suggests that RE inactivation impairs extinction learning, it is…

Dopamine participates in encoding memories and could either encode rewarding/aversive value of unconditioned stimuli or act as a novelty signal triggering contextual learning. Here we show that intraperitoneal injection of the dopamine D1/5R antagonist SCH23390 impairs contextual fear conditioning and tone-shock association, while intrahippocampal…

Damage to the hippocampus (HPC) typically causes retrograde amnesia for contextual fear conditioning. Repeating the conditioning over several sessions, however, can eliminate the retrograde amnesic effects. This form of reinstatement thus permits modifications to networks that can support context memory retrieval in the absence of the HPC. The…

Fear generalization is one of the main symptoms of posttraumatic stress disorder. In rodents, the anterior cingulate cortex (ACC) and the hippocampus (HPC) control the expression of contextual fear memory generalization. Consistently, ACC projections to the ventral HPC contribute to contextual fear generalization. However, the roles of ACC…

It has been reported that during chemotherapy treatment, some patients can experience nausea before pharmacological administration, suggesting that contextual stimuli are associated with the nauseating effects. There are attempts to reproduce with animal models the conditions under which this phenomenon is observed to provide a useful paradigm for…

Strong evidence supports a role for protein degradation in fear memory formation. However, these data have been largely done in only male animals. Here, we found that following contextual fear conditioning, females, but not males, had increased levels of proteasome activity and K48 polyubiquitin protein targeting in the dorsal hippocampus, the…

Operant reward learning of feeding behavior in "Aplysia" increases the frequency and regularity of biting, as well as biases buccal motor patterns (BMPs) toward ingestion-like BMPs (iBMPs). The engram underlying this memory comprises cells that are part of a central pattern generating (CPG) circuit and includes increases in the intrinsic…

Reconsolidation is a time-limited process under which reactivated memory content can be modified. Works focused on studying reconsolidation mainly restrict intervention to the moments immediately after reactivation and to recently acquired memories. However, the brain areas activated during memory retrieval depend on when it was acquired, and it…

Dysfunctions in memory recall lead to pathological fear; a hallmark of trauma-related disorders, like posttraumatic stress disorder (PTSD). Both, heightened recall of an association between a cue and trauma, as well as impoverished recall that a previously trauma-related cue is no longer a threat, result in a debilitating fear toward the cue.…

Reduction in the expression or function of [alpha]5-subunit-containing GABA[subscript A] receptors ([alpha]5GABA[subscript A]Rs) leads to improvement in several hippocampus-dependent memory domains. However, studies thus far mostly lack anatomical specificity in terms of neuronal circuits and populations. We demonstrate that mice with a selective…

Learning and memory involves a large neural network of many brain regions, including the notable hippocampus along with the retrosplenial cortex (RSC) and lateral septum (LS). Previous studies have established that the dorsal hippocampus (dHPC) plays a critical role during the acquisition and retrieval/expression of episodic memories. However, the…

Early experiences with sexual reward play a pivotal role in the formation of sexual behavior and partner preference. Associations of salient partner cues, or even neutral cues on a partner, with sexual reward states are a product of Pavlovian learning. However, the extent to which first experiences that associate a neutral stimulus with no…

Hippocampal lesions often produce temporally graded retrograde amnesia (TGRA), whereby recent memory is impaired more than remote memory. This finding has provided support for the process of systems consolidation. However, temporally graded memory impairment has not been observed with the watermaze task, and the findings have been inconsistent…

Conditioned fear memories that are context-specific shortly after conditioning generalize over time. We exposed rats to a context reminder 30 d after conditioning, which served to reinstate context-specificity, and investigated how this reminder alters retrieval-induced activity in the hippocampus and anterior cingulate cortex (aCC) relative to a…

The context preexposure facilitation effect (CPFE) is a contextual fear conditioning paradigm in which learning about the context, acquiring the context-shock association, and retrieving/expressing contextual fear are temporally dissociated into three distinct phases. In contrast, learning about the context and the context-shock association…