Comparing behaviours induced by natural memory retrieval and optogenetic reactivation of an engram ensemble in mice.

Memories are thought to be stored within sparse collections of neurons known as engram ensembles. Neurons active during a training episode are allocated to an engram ensemble ('engram neurons'). Memory retrieval is initiated by external sensory or internal cues present at the time of training reactivating engram neurons.

Hyperpolarized [1-13C] pyruvate MR spectroscopy detect altered glycolysis in the brain of a cognitively impaired mouse model fed high-fat diet.

Higher dietary intakes of saturated fatty acid increase the risk of developing Alzheimer's disease and dementia, and even in people without diabetes higher glucose levels may be a risk factor for dementia. The mechanisms causing neuronal dysfunction and dementia by consuming high-fat diet degrading the integrity of the blood-brain barrier (BBB) has been suggested but are not yet fully understood, and metabolic state of the brain by this type of insult is still veiled. The objective of this study was to investigate the effect of high-fat diet on the brain metabolism by a multimodal imaging method using the hyperpolarizedcarbon 13 (C)-pyruvate magnetic resonance (MR) spectroscopy and dynamic contrast-enhanced MR imaging in conjunction with the biochemical assay and the behavior test in a mouse model fed high-fat diet (HFD).

Activation of the dopamine D receptor can extend long-term spatial memory persistence via PKA signaling in mice.

Many works have been performed to understand the mechanisms of the formation and persistence of memory. However, it is not fully understood whether the decay of long-term memory can be modulated by the activation of dopamine D receptor. A Barnes maze task was employed to measure long-term spatial memory.

Fluoxetine Inhibits Natural Decay of Long-Term Memory via Akt/GSK-3β Signaling.

Understanding the mechanisms underlying the natural decay of long-term memory can help us find means of extending the duration of long-term memory. However, the neurobiological processes involved in the decay of long-term memory are poorly understood. In the present study, we examined the effect of acute and chronic treatment of fluoxetine on natural decay of long-term memory and the possible mechanism.

Swertisin, a C-glucosylflavone, ameliorates scopolamine-induced memory impairment in mice with its adenosine A1 receptor antagonistic property.

Swertisin, a C-glucosylflavone isolated from Swertia japonica, has been known to have anti-inflammatory or antidiabetic activities. Until yet, however, its cognitive function is not investigated. In the present study, we endeavored to elucidate the effects of swertisin on cholinergic blockade-induced memory impairment.

Nodakenin Enhances Cognitive Function and Adult Hippocampal Neurogenesis in Mice.

In our previous study, we demonstrated that nodakenin, a coumarin compound isolated from Angelica decursiva, ameliorates learning and memory impairments induced by scopolamine. In the present study, we investigated the effects of nodakenin on the cognitive function in the normal naïve mice in a passive avoidance task, and the results showed that nodakenin significantly increased the latency time in normal naïve mice. In addition, sub-chronic administration of nodakenin increased the number of 5-bromo-2-deoxyuridine (BrdU)-positive cells in the hippocampal dentate gyrus (DG) region.

Spinosin, a C-Glucosylflavone, from Zizyphus jujuba var. spinosa Ameliorates Aβ1-42 Oligomer-Induced Memory Impairment in Mice.

Alzheimer's disease (AD) is a neurodegenerative disorder associated with progressive memory loss and neuronal cell death. Although numerous previous studies have been focused on disease progression or reverse pathological symptoms, therapeutic strategies for AD are limited. Alternatively, the identification of traditional herbal medicines or their active compounds has received much attention.

Oleanolic acid attenuates MK-801-induced schizophrenia-like behaviors in mice.

Schizophrenia is a severe neuropsychiatric disorder that is characterized by core psychiatric symptoms, including positive, negative, and cognitive symptoms. Current treatments for schizophrenia have an effect on positive symptoms but have a limited efficacy on negative or cognitive symptoms. Oleanolic acid is a plant-derived pentacyclic terpenoid that is known to exhibit anti-oxidative and anti-inflammatory activities.