Age-related vulnerability of pattern separation in C57BL/6J mice.

Aging is associated with impaired performance in behavioral pattern separation (PS) tasks based on similarities in object features and in object location. These deficits have been attributed to functional alterations in the dentate gyrus (DG)-CA3 region. Animal studies suggested a role of adult-born DG neurons in PS performance.

Differential contribution of APP metabolites to early cognitive deficits in a TgCRND8 mouse model of Alzheimer's disease.

Alzheimer's disease (AD) is a neurodegenerative pathology commonly characterized by a progressive and irreversible deterioration of cognitive functions, especially memory. Although the etiology of AD remains unknown, a consensus has emerged on the amyloid hypothesis, which posits that increased production of soluble amyloid β (Aβ) peptide induces neuronal network dysfunctions and cognitive deficits. However, the relative failures of Aβ-centric therapeutics suggest that the amyloid hypothesis is incomplete and/or that the treatments were given too late in the course of AD, when neuronal damages were already too extensive.

APOE-Sensitive Cholinergic Sprouting Compensates for Hippocampal Dysfunctions Due to Reduced Entorhinal Input.

Unlabelled: Brain mechanisms compensating for cerebral lesions may mitigate the progression of chronic neurodegenerative disorders such as Alzheimer's disease (AD). Mild cognitive impairment (MCI), which often precedes AD, is characterized by neuronal loss in the entorhinal cortex (EC). This loss leads to a hippocampal disconnection syndrome that drives clinical progression.

Spatial Reference Memory is Associated with Modulation of Theta-Gamma Coupling in the Dentate Gyrus.

Spatial reference memory in rodents represents a unique opportunity to study brain mechanisms responsible for encoding, storage and retrieval of a memory. Even though its reliance on hippocampal networks has long been established, the precise computations performed by different hippocampal subfields during spatial learning are still not clear. To study the evolution of electrophysiological activity in the CA1-dentate gyrus axis of the dorsal hippocampus over an iterative spatial learning paradigm, we recorded local field potentials in behaving mice using a newly designed appetitive version of the Barnes maze.

Defective response inhibition and collicular noradrenaline enrichment in mice with duplicated retinotopic map in the superior colliculus.

The superior colliculus is a hub for multisensory integration necessary for visuo-spatial orientation, control of gaze movements and attention. The multiple functions of the superior colliculus have prompted hypotheses about its involvement in neuropsychiatric conditions, but to date, this topic has not been addressed experimentally. We describe experiments on genetically modified mice, the Isl2-EphA3 knock-in line, that show a well-characterized duplication of the retino-collicular and cortico-collicular axonal projections leading to hyperstimulation of the superior colliculus.

Reduced plasticity and mild cognitive impairment-like deficits after entorhinal lesions in hAPP/APOE4 mice.

Mild cognitive impairment (MCI) is a clinical condition that often precedes Alzheimer disease (AD). Compared with apolipoprotein E-ε3 (APOE3), the apolipoprotein E-ε4 (APOE4) allele is associated with an increased risk of developing MCI and spatial navigation impairments. In MCI, the entorhinal cortex (EC), which is the main innervation source of the dentate gyrus, displays partial neuronal loss.

ApoE4 confers better spatial memory than apoE3 in young adult hAPP-Yac/apoE-TR mice.

The APOE-ɛ4 allele is associated with increased cognitive decline during normal aging and Alzheimer's disease. However, several studies intriguingly found a beneficial effect on cognition in young adult human APOE-ɛ4 carriers. Here, we show that 3-month old bigenic hAPP-Yac/apoE4-TR mice outperformed their hAPP-Yac/apoE3-TR counterparts on learning and memory performances in the highly hippocampus-dependent, hidden-platform version of the Morris water maze task.