A specific role for hippocampal mossy fiber's zinc in rapid storage of emotional memories.

We investigated the specific role of zinc present in large amounts in the synaptic vesicles of mossy fibers and coreleased with glutamate in the CA3 region. In previous studies, we have shown that blockade of zinc after release has no effect on the consolidation of spatial learning, while zinc is required for the consolidation of contextual fear conditioning. Although both are hippocampo-dependent processes, fear conditioning to the context implies a strong emotional burden.

1H NMR metabolomic signatures in five brain regions of the AβPPswe Tg2576 mouse model of Alzheimer's disease at four ages.

In the quest for biomarkers of onset and progression of Alzheimer's disease, a 1H NMR-based metabolomic study was performed on the simple single-transgenic Tg2576 mouse model. These mice develop a slow cognitive decline starting by 6 months and express amyloid plaques from 10 months of age. The metabolic profiles of extracts from five brain regions (frontal cortex, rhinal cortex, hippocampus, midbrain, and cerebellum) of Tg2576 male mice were compared to those of controls, at 1, 3, 6 and 11 months of age.

Modifications of hippocampal circuits and early disruption of adult neurogenesis in the tg2576 mouse model of Alzheimer's disease.

At advanced stages of Alzheimer's disease, cognitive dysfunction is accompanied by severe alterations of hippocampal circuits that may largely underlie memory impairments. However, it is likely that anatomical remodeling in the hippocampus may start long before any cognitive alteration is detected. Using the well-described Tg2576 mouse model of Alzheimer's disease that develops progressive age-dependent amyloidosis and cognitive deficits, we examined whether specific stages of the disease were associated with the expression of anatomical markers of hippocampal dysfunction.

Differential needs of zinc in the CA3 area of dorsal hippocampus for the consolidation of contextual fear and spatial memories.

One peculiarity of the hippocampal CA3 mossy fiber terminals is the co-release of zinc and glutamate upon synaptic transmission. How these two players act on hippocampal-dependent memories is still unclear. To decipher their respective involvement in memory consolidation, a pharmacological approach was chosen.

Copper chelator induced efficient episodic memory recovery in a non-transgenic Alzheimer's mouse model.

Alzheimer's disease (AD) is a neurodegenerative syndrom involving many different biological parameters, including the accumulation of copper metal ions in Aβ amyloid peptides due to a perturbation of copper circulation and homeostasis within the brain. Copper-containing amyloids activated by endogenous reductants are able to generate an oxidative stress that is involved in the toxicity of abnormal amyloids and contribute to the progressive loss of neurons in AD. Since only few drugs are currently available for the treatment of AD, we decided to design small molecules able to interact with copper and we evaluated these drug-candidates with non-transgenic mice, since AD is mainly an aging disease, not related to genetic disorders.

Transient enriched housing before amyloidosis onset sustains cognitive improvement in Tg2576 mice.

Levels of educational and occupational attainment, as components of cognitive reserve, may modify the relationship between the pathological hallmarks and cognition in Alzheimer's disease (AD). We examined whether exposure of a Tg2576 transgenic mouse model of AD to environmental enrichment (EE) at a specific period during the amyloidogenic process favored the establishment of a cognitive reserve. We found that exposure to EE during early adulthood of Tg2576 mice--before amyloidogenesis has started--reduced the severity of AD-related cognitive deficits more efficiently than exposure later in life, when the pathology is already present.

Central locomotor and cognitive effects of a NPFF receptor agonist in mouse.

NPFF receptors are expressed in several brain regions directly or indirectly involved in cognition and behavior. However, the cognitive effects of the NPFF system have been poorly studied. Therefore, the aim of our study was to analyze the effects of i.

Activation of metabotropic glutamate receptor type 2/3 supports the involvement of the hippocampal mossy fiber pathway on contextual fear memory consolidation.

Elucidating the functional properties of the dentate gyrus (DG), CA3, and CA1 areas is critical for understanding the role of the dorsal hippocampus in contextual fear memory processing. In order to specifically disrupt various hippocampal inputs, we used region-specific infusions of DCG-IV, the metabotropic glutamate receptor agonist, which selectively disrupts entorhinal outputs as well as mossy fiber transmission in the hippocampus. The consequences of these injections were studied using a contextual fear conditioning (CFC) paradigm.

A preliminary study of the effects of handling type on horses' emotional reactivity and the human-horse relationship.

Handling is a crucial component of the human-horse relationship. Here, we report data from an experiment conducted to assess and compare the effect of two training methods. Two groups of six Welsh mares were trained during four sessions of 50 min, one handled with traditional exercises (halter leading, grooming/brushing, lifting feet, lunging and pseudo-saddling (using only girth and saddle pad) and the second group with natural horsemanship exercises (desensitization, yielding to body pressure, lunging and free-lunging).

Involvement of hippocampal CA3 K(ATP) channels in contextual memory.

This paper evaluates the involvement of hippocampal ATP-sensitive potassium channels (K(ATP)) in learning and memory. After confirming expression of the Kir6.2 subunit in the CA3 region of C57BL/6J mice, we performed intra-hippocampal pharmacological injections of specific openers and blockers of K(ATP) channels.

Effects of the genetic background on cognitive performances of TG2576 mice.

Animal models of genetic diseases obtained by transferring human mutated genes in the mouse are widely used in biomedical based research. They constitute efficient tools to study mechanisms underlying abnormal phenotypes. Unfortunately, the phenotype of the transgene is often obscured by the genetic background of the embryonic stem cells and that of the recipient strain used to create the transgenic line.

Transient activation of the CA3 Kappa opioid system in the dorsal hippocampus modulates complex memory processing in mice.

The hippocampus plays a central role in various forms of complex learning and memory. Opioid peptides and receptors are abundant in the hippocampus. These peptides are co-released with glutamate from mossy fiber- and lateral perforant path-synapses.

A neuropeptide FF agonist blocks the acquisition of conditioned place preference to morphine in C57Bl/6J mice.

Neuropeptide FF behaves as an opioid-modulating peptide that seems to be involved in morphine tolerance and physical dependence. Nevertheless, the effects of neuropeptide FF agonists on the rewarding properties of morphine remain unknown. C57BL6 mice were conditioned in an unbiased balanced paradigm of conditioned place preference to study the effect of i.

Encoding, consolidation, and retrieval of contextual memory: differential involvement of dorsal CA3 and CA1 hippocampal subregions.

Studies on human and animals shed light on the unique hippocampus contributions to relational memory. However, the particular role of each hippocampal subregion in memory processing is still not clear. Hippocampal computational models and theories have emphasized a unique function in memory for each hippocampal subregion, with the CA3 area acting as an autoassociative memory network and the CA1 area as a critical output structure.

The Collaborative Cross, a community resource for the genetic analysis of complex traits.

The goal of the Complex Trait Consortium is to promote the development of resources that can be used to understand, treat and ultimately prevent pervasive human diseases. Existing and proposed mouse resources that are optimized to study the actions of isolated genetic loci on a fixed background are less effective for studying intact polygenic networks and interactions among genes, environments, pathogens and other factors. The Collaborative Cross will provide a common reference panel specifically designed for the integrative analysis of complex systems and will change the way we approach human health and disease.

Disruption of hippocampal CA3 network: effects on episodic-like memory processing in C57BL/6J mice.

Lesion studies have demonstrated the prominent role of the hippocampus in spatial and contextual learning. To better understand how contextual information is processed in the CA3 region during learning, we focused on the CA3 autoassociative network hypothesis. We took advantage of a particularity of the mossy fibre (MF) synapses, i.

Siah-1b is a direct transcriptional target of p53: identification of the functional p53 responsive element in the siah-1b promoter.

Siah proteins are E3 ubiquitin ligases. They are homologues of the Drosophila seven in absentia (Sina), a protein required for the R7 photoreceptor development. We have previously found that the expression of human siah-1 and its mouse homologue siah-1b are induced by p53 during apoptosis and tumor reversion.