The laterodorsal thalamic nucleus (LD) is believed to play roles in learning and memory, especially spatial tasks. However, the molecular mechanism that underlies the cognitive process in the LD remains unclear and needs to be investigated. So far, there is plenty of evidence indicating that plasticity has been in some of the cortical or…

Evidence suggests encoding of recent episodic experiences may be enhanced by a subsequent salient event. We tested this hypothesis by giving rats a 3-min unsupervised experience with four odors and measuring retention after different delays. Animals recognized that a novel element had been introduced to the odor set at 24 but not 48 h. However,…

Research into the neural mechanisms that underlie higher-order cognitive control of eating behavior suggests that ventral hippocampal (vHC) neurons, which are critical for emotional memory, also inhibit energy intake. We showed previously that optogenetically inhibiting vHC glutamatergic neurons during the early postprandial period, when the…

In obsessive-compulsive disorder (OCD), functional behaviors such as checking that a door is locked become dysfunctional, maladaptive, and debilitating. However, it is currently unknown how aversive and appetitive motivations interact to produce functional and dysfunctional behavior in OCD. Here we show a double dissociation in the effects of…

In the olfactory bulb, a cAMP/PKA/CREB-dependent form of learning occurs in the first week of life that provides a unique mammalian model for defining the epigenetic role of this evolutionarily ancient plasticity cascade. Odor preference learning in the week-old rat pup is rapidly induced by a 10-min pairing of odor and stroking. Memory is…

We investigated whether cycloheximide (CHX) would induce amnesia for the stress-induced impairment of extinction retrieval. First, a single restraint stress session was demonstrated to impair extinction retrieval, but not fear conditioning. A second experiment showed that when CHX was administered immediately after restraint, rats exhibited…

Signaled active avoidance (SAA) behavior requires the suppression of defensive reactions, such as freezing, that conflict with the avoidance response. The neural mechanisms of this inhibitory process are not well understood. Here, we demonstrate that ventromedial prefrontal cortex projections to the nucleus reuniens of the thalamus are recruited…

There are sex differences in anxiety disorders with regard to occurrence and severity of episodes such that females tend to experience more frequent and more severe episodes. Contextual fear learning and generalization are especially relevant to anxiety disorders, which are often defined by expressing fear and/or anxiety in safe contexts. In…

Gene transcription is a crucial step in the sequence of molecular, synaptic, cellular, and systems mechanisms underlying learning and memory. Here, we review the experimental evidence demonstrating that alterations in the levels and functionality of the methylated DNA-binding transcriptional regulator MeCP2 are implicated in the learning and…

Episodic memories formed during infancy are rapidly forgotten, a phenomenon associated with infantile amnesia, the inability of adults to recall early-life memories. In both rats and mice, infantile memories, although not expressed, are actually stored long term in a latent form. These latent memories can be reinstated later in life by certain…

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…

A prominent theory of category learning, COVIS, posits that new categories are learned with either a declarative or procedural system, depending on the task. The declarative system uses the prefrontal cortex (PFC) to learn rule-based (RB) category tasks in which there is one relevant sensory dimension that can be used to establish a rule for…

Hippocampal dopamine D1/D5 receptor-dependent destabilization is necessary for object recognition memory (ORM) updating through reconsolidation. Dopamine also regulates hippocampal theta and gamma oscillations, which are involved in novelty and memory processing. We found that, in adult male rats, ORM recall in the presence of a novel object, but…

In signaled active avoidance (SigAA), rats learn to suppress Pavlovian freezing and emit actions to remove threats and prevent footshocks. SigAA is critical for understanding aversively motivated instrumental behavior and anxiety-related active coping. However, with standard protocols ~25% of rats exhibit high freezing and poor avoidance. This has…

While interest in active avoidance has recently been resurgent, many concerns relating to the nature of this form of learning remain unresolved. By separating stimulus and response acquisition, aversive Pavlovian-instrumental transfer can be used to measure the effect of avoidance learning on threat processing with more control than typical…