The epigenome serves as a signal integration platform that encodes information from experience and environment that adds tremendous complexity to the regulation of transcription required for memory, beyond the directions encoded in the genome. To date, our understanding of how epigenetic mechanisms integrate information to regulate gene expression…

Honeybees are a standard model for the study of appetitive learning and memory. Yet, fewer attempts have been performed to characterize aversive learning and memory in this insect and uncover its molecular underpinnings. Here, we took advantage of the positive phototactic behavior of bees kept away from the hive in a dark environment and…

We investigated the in vivo role of protein degradation during intermediate (ITM) and long-term memory (LTM) in "Aplysia" using an operant learning paradigm. The proteasome inhibitor MG-132 inhibited the induction and molecular consolidation of LTM with no effect on ITM. Remarkably, maintenance of steady-state protein levels through…

Habituation is a highly conserved phenomenon that remains poorly understood at the molecular level. Invertebrate model systems, like "Caenorhabditis elegans," can be a powerful tool for investigating this fundamental process. Here we established a high-throughput learning assay that used real-time computer vision software for behavioral…

In a dynamic environment, there is an adaptive value in the ability of animals to acquire and express memories. That both simple and complex animals can learn is therefore not surprising. How animals have solved this problem genetically and anatomically probably lies somewhere in a range between a single molecular/anatomical mechanism that applies…

Pyramidal neurons in the piriform cortex from olfactory-discrimination (OD) trained rats undergo synaptic modifications that last for days after learning. A particularly intriguing modification is reduced paired-pulse facilitation (PPF) in the synapses interconnecting these cells; a phenomenon thought to reflect enhanced synaptic release. The…

Persistent drug seeking/taking behavior involves the consolidation of memory. With each drug use, the memory may be reactivated and reconsolidated to maintain the original memory. During reactivation, the memory may become labile and susceptible to disruption; thus, molecules involved in plasticity should influence acquisition and/or…

We proposed that mitral cell [beta]1-adrenoceptor activation mediates rat pup odor preference learning. Here we evaluate [beta]1-, [beta]2-, [alpha]1-, and [alpha]2-adrenoceptor agonists in such learning. The [beta]1-adrenoceptor agonist, dobutamine, and the [alpha]1-adrenoceptor agonist, phenylephrine, induced learning, and both exhibited an…

Post-retrieval interference with a memory has uncovered a phenomenon known to the field as reconsolidation. In this article, we will review the specific molecular mechanisms that have been implicated in reconsolidation. As a result of numerous studies over the past five years, it can now be said with a fair amount of certainty that reconsolidation…

In the adult brain, the expression of NT-3 is largely confined to the hippocampal dentate gyrus (DG), an area exhibiting significant neurogenesis. Using a conditional mutant line in which the "NT-3" gene is deleted in the brain, we investigated the role of NT-3 in adult neurogenesis, hippocampal plasticity, and memory. Bromodeoxyuridine…

The [delta] subunit of the GABA[subscript [Alpha]] receptor (GABA[subscript [Alpha]]R) is highly expressed in the dentate gyrus of the hippocampus. Genetic deletion of this subunit reduces synaptic and extrasynaptic inhibition and decreases sensitivity to neurosteroids. This paper examines the effect of these changes on hippocampus-dependent trace…