We observed differences in cognitive functions between middle-aged female and male Wistar rats. Both (like youngsters) discriminated new versus familiar objects, showing similar short- and long-term memory (STM and LTM, respectively). Only females show robust LTM for new location of an object. Both successfully form LTM of inhibitory avoidance,…

Binding visual features into coherent object representations is essential both in short- and long-term memory. However, the relationship between feature binding processes at different memory delays remains unexplored. Here, we addressed this question by using the Mnemonic Similarity Task and a delayed-estimation working memory task on a large…

Humans routinely use past experience with complexity to deal with novel, challenging circumstances. This fundamental aspect of real-world behavior has received surprisingly little attention in animal studies, and the underlying brain mechanisms are unknown. The present experiments tested for transfer from past experience in rats and then used…

The formation of long-term memory requires signaling from the synapse to the nucleus to mediate neuronal activity-dependent gene transcription. Synapse-to-nucleus communication is initiated by influx of calcium ions through synaptic NMDA receptors and/or L-type voltage-gated calcium channels and involves the activation of transcription factors by…

Developed as a tool to assess working memory capacity in rodents, the odor span task (OST) has significant potential to advance drug discovery in animal models of psychiatric disorders. Prior investigations indicate OST performance is impaired by systemic administration of N-methyl-D-aspartate receptor (NMDA-r) antagonists and is sensitive to…

To test the hypothesis that thalamic midline nuclei play a transient role in memory consolidation, we reanalyzed a prospective functional MRI study, contrasting recent and progressively more remote memory retrieval. We revealed a transient thalamic connectivity increase with the hippocampus, the medial prefrontal cortex (mPFC), and a…

Here we examine the role of the exchange protein directly activated by cAMP (Epac) in ß-adrenergic-dependent associative odor preference learning in rat pups. Bulbar Epac agonist (8-pCPT-2-O-Me-cAMP, or 8-pCPT) infusions, paired with odor, initiated preference learning, which was selective for the paired odor. Interestingly, pairing odor with Epac…

Structures in the medial temporal lobe, including the hippocampus and perirhinal cortex, are known to be essential for the formation of long-term memory. Recent animal and human studies have investigated whether perirhinal cortex might also be important for visual perception. In our study, using a simultaneous oddity discrimination task, rats with…

Memory is a dynamic process that allows encoding, storage, and retrieval of information acquired through individual experience. In the honeybee "Apis mellifera," olfactory conditioning of the proboscis extension response (PER) has shown that besides short-term memory (STM) and mid-term memory (MTM), two phases of long-term memory (LTM)…

Protein synthesis is involved in the consolidation of short-term memory into long-term memory. Previous electrophysiological data concerning LTP in CA3 suggest that protein synthesis in that region might also be necessary for short-term memory. We tested this hypothesis by locally injecting the protein synthesis inhibitor anisomycin in hippocampal…

In classical conditioning, the temporal sequence of stimulus presentations is critical for the association between the conditioned stimulus (CS) and the unconditioned stimulus (US). In forward conditioning, the CS precedes the US and is learned as a predictor for the US. Thus it acquires properties to elicit a behavioral response, defined as…

Neonatal odor-preference memory in rat pups is a well-defined associative mammalian memory model dependent on cAMP. Previous work from this laboratory demonstrates three phases of neonatal odor-preference memory: short-term (translation-independent), intermediate-term (translation-dependent), and long-term (transcription- and…

The consolidation process from short- to long-term memory depends on the type of stimulation received from a specific neuronal network and on the cooperativity and associativity between different synaptic inputs converging onto a specific neuron. We show here that the plasticity thresholds for inducing LTP are different in proximal and distal…

Learning induces dynamic changes to the actin cytoskeleton that are required to support memory formation. However, the molecular mechanisms that mediate filamentous actin (F-actin) dynamics during learning and memory are poorly understood. Myosin II motors are highly expressed in actin-rich growth structures including dendritic spines, and we have…

Early studies of memory-impaired patients with medial temporal lobe (MTL) damage led to the view that the hippocampus and related MTL structures are involved in the formation of long-term memory and that immediate memory and working memory are independent of these structures. This traditional idea has recently been revisited. Impaired performance…