We investigated whether reexposure to an amnestic agent would reverse amnesia for extinction of learned fear similar to that of a reactivated memory. When cycloheximide (CHX) was administered immediately after a brief cue-induced memory reactivation (15 sec) and an extended extinction session (12 min) rats showed retrograde amnesia for both…

Learning to navigate toward a goal is an essential skill. Place learning is thought to rely on the ability of animals to associate the location of a goal with surrounding environmental cues. Using the Morris water maze, a task popularly used to examine place learning, we demonstrate that distal cues provide animals with distance and directional…

A distributed limbic-corticostriatal circuitry is implicated in cue-induced drug craving and relapse. Exposure to drug-paired cues not only precipitates relapse, but also triggers the reactivation and reconsolidation of the cue-drug memory. However, the limbic cortical-striatal circuitry underlying drug memory reconsolidation is unclear. The aim…

Individuals with anxiety disorders often do not respond to safety signals and hence continue to be afraid and anxious. Consequently, it is important to develop paradigms in animals that can directly study brain systems involved in learning about, and responding to, safety signals. We previously developed a discrimination procedure in rats of the…

Neuronal modifications that accompany normal aging occur in brain neuropils and might share commonalties across phyla including the most successful group, the Insecta. This study addresses the kinds of neuronal modifications associated with loss of memory that occur in the hemimetabolous insect "Periplaneta americana." Among insects that display…

The crucial role of the medial temporal lobe (MTL) in episodic memory is well established. Although there is little doubt that its anatomical subregions--the hippocampus, peri-, entorhinal and parahippocampal cortex (PHC)--contribute differentially to mnemonic processes, their specific functions in episodic memory are under debate. Data from…

The present work introduces a form of associative mechanosensory conditioning of the proboscis extension reflex (PER) in honeybees. In our paradigm, harnessed honeybees learn the elemental association between mechanosensory, antennal stimulation and a reward of sucrose solution delivered to the proboscis. Thereafter, bees extend their proboscis to…

Courtship conditioning is an associative learning paradigm in "Drosophila melanogaster," wherein male courtship behavior is modified by experience with unreceptive, previously mated females. While the training experience with mated females involves multiple sensory and behavioral interactions, the authors hypothesized that female cuticular…