In previous studies using male rodents, context change disrupted a fear response at a short, but not a long, retention interval. Here, we examined the effects of context changes on fear responses as a function of time in male and female rats. Males displayed context discrimination at all intervals, whereas females exhibited generalization by 5 d.…

A common source of variance (i.e., "general intelligence") underlies an individual's performance across diverse tests of cognitive ability, and evidence indicates that the processing efficacy of working memory may serve as one such source of common variance. One component of working memory, selective attention, has been reported to…

Lesion and inactivation studies indicate that the central amygdala (CeA) participates in the expression of cued and contextual fear, whereas the bed nucleus of the stria terminalis (BNST) is only involved in the latter. The basis for this functional dissociation is unclear because CeA and BNST form similar connections with the amygdala and…

Exercise can have many benefits for the body, but it also benefits the brain by increasing neurogenesis, synaptic plasticity, and performance on learning and memory tasks. The period of exercise needed to realize the structural and functional benefits for the brain have not been well delineated, and previous studies have used periods of exercise…

Learning by repetition engages distinct cognitive strategies whose contributions are adjusted with experience. Early in learning, performance relies upon flexible, attentive strategies. With extended practice, inflexible, automatic strategies emerge. This transition is thought fundamental to habit formation and applies to human and animal…

In four experiments, we explored the capacity for spatial mental imagery in patients with hippocampal lesions, using tasks that minimized the role of learning and memory. On all four tasks, patients with hippocampal lesions performed as well as controls. Nonetheless, in separate tests, the patients were impaired at remembering the materials that…

Growth factor (GF) signaling is critically important for developmental plasticity. It also plays a crucial role in adult plasticity, such as that required for memory formation. Although different GFs interact with receptors containing distinct types of kinase domains, they typically signal through converging intracellular cascades (e.g.,…

According to the standard model of systems consolidation (SMC), neocortical circuits are reactivated during the retrieval of declarative memories. This process initially requires the hippocampus. However, with the passage of time, neocortical circuits become strengthened and can eventually retrieve memory without input from the hippocampus.…

Parkinson's disease (PD) has been, until recently, mainly defined by the presence of characteristic motor symptoms, such as rigidity, tremor, bradykinesia/akinesia, and postural instability. Accordingly, pharmacological and surgical treatments have so far addressed these motor disturbances, leaving nonmotor, cognitive deficits an unmet…

Recent studies in "Aplysia" have identified a new variation of synaptic plasticity in which modulatory transmitters enhance spontaneous release of glutamate, which then acts on postsynaptic receptors to recruit mechanisms of intermediate- and long-term plasticity. In this review I suggest the hypothesis that similar plasticity occurs in…

Here we examined effects of acute stressors that involve either systemic coadministration of corticosterone/yohimbine (3 mg/kg each) to increase glucocorticoid/noradrenaline activity (denoted as "pharmacological" stressor) or one or several distinct restraint stressors (denoted as "single" vs. "multiple" stressor) on…

In the adult mammalian brain, newly generated neurons are continuously incorporated into two networks: interneurons born in the subventricular zone migrate to the olfactory bulb, whereas the dentate gyrus (DG) of the hippocampus integrates locally born principal neurons. That the rest of the mammalian brain loses significant neurogenic capacity…

Calcitonin gene-related peptide (CGRP) infusions into the bed nucleus of the stria terminalis (BNST) evoke increases in startle amplitude and increases in anxiety-like behavior in the plus maze. Conversely, intra-BNST infusions of the CGRP antagonist CGRP[subscript 8-37] block unconditioned startle increases produced by fox odor. Here we evaluate…

Pairing a previously neutral conditioned stimulus (CS; e.g., a tone) to an aversive unconditioned stimulus (US; e.g., a footshock) leads to associative learning such that the tone alone comes to elicit a conditioned response (e.g., freezing). We have previously shown that an extinction session that occurs within the reconsolidation window…

In reconsolidation studies, memories are typically retrieved by an exposure to a single conditioned stimulus (CS). We have previously demonstrated that reconsolidation processes are CS-selective, suggesting that memories retrieved by the CS exposure are discrete and reconsolidate separately. Here, using a compound stimulus in which two distinct…