memory impairment

Hippocampal network dynamics during impaired working memory in epileptic mice

Memory impairment is a common cognitive deficit in temporal lobe epilepsy (TLE). The hippocampus is severely altered in TLE exhibiting multiple anatomical changes that lead to a hyperexcitable network capable of generating frequent epileptic discharges and seizures. In this study we investigated whether hippocampal involvement in epileptic activity drives working memory deficits using bilateral LFP recordings from CA1 during task performance. We discovered that epileptic mice experienced focal rhythmic discharges (FRDs) while they performed the spatial working memory task. Spatial correlation analysis revealed that FRDs were often spatially stable on the maze and were most common around reward zones (25 ‰) and delay zones (50 ‰). Memory performance was correlated with stability of FRDs, suggesting that spatially unstable FRDs interfere with working memory codes in real time.

Western diet consumption and memory impairment: what, when, and how?

Habitual consumption of a “Western diet”, containing higher than recommended levels of simple sugars and saturated fatty acids, is associated with cognitive impairments in humans and in various experimental animal models. Emerging findings reveal that the specific mnemonic processes that are disrupted by Western diet consumption are those that rely on the hippocampus, a brain region classically linked with memory control and more recently with the higher-order control of food intake. Our laboratory has established rat models in which excessive consumption of different components of a Western diet during the juvenile and adolescent periods of development yields long-term impairments in hippocampal-dependent memory function without concomitant increases in total caloric intake, body weight, or adiposity. Our ongoing work is investigating alterations in the gut microbiome as a potential underlying neurobiological mechanism linking early life unhealthy dietary factors to adverse neurocognitive outcomes.

Disinhibitory and neuromodulatory regulation of hippocampal synaptic plasticity

The CA1 pyramidal neurons are embedded in an intricate local circuitry that contains a variety of interneurons. The roles these interneurons play in the regulation of the excitatory synaptic plasticity remains largely understudied. Recent experiments showed that repeated cholinergic activation of 𝛼7 nACh receptors expressed in oriens-lacunosum-moleculare (OLM𝛼2) interneurons could induce LTP in SC-CA1 synapses. We used a biophysically realistic computational model to examine mechanistically how cholinergic activation of OLMa2 interneurons increases SC to CA1 transmission. Our results suggest that, when properly timed, activation of OLMa2 interneurons cancels the feedforward inhibition onto CA1 pyramidal cells by inhibiting fast-spiking interneurons that synapse on the same dendritic compartment as the SC, i.e., by disinhibiting the pyramidal cell dendritic compartment. Our work further describes the pairing of disinhibition with SC stimulation as a general mechanism for the induction of synaptic plasticity. We found that locally-reduced GABA release (disinhibition) paired with SC stimulation could lead to increased NMDAR activation and intracellular calcium concentration sufficient to upregulate AMPAR permeability and potentiate the excitatory synapse. Our work suggests that inhibitory synapses critically modulate excitatory neurotransmission and induction of plasticity at excitatory synapses. Our work also shows how cholinergic action on OLM interneurons, a mechanism whose disruption is associated with memory impairment, can down-regulate the GABAergic signaling into CA1 pyramidal cells and facilitate potentiation of the SC-CA1 synapse.

5xFAD mice present memory impairments and reduced TrkB-FL levels that were reverted after TAT-TrkB administration

Age-specific memory impairment induced by co-exposure to nicotine and a synthetic cannabinoid in mice

Allosteric modulation of AhR by 3,3’-diindolylmethane can prevent recognition memory impairment caused by binge-ethanol exposure

Evidence of working memory impairment at 8-11 months postpartum in women with history of SARS-CoV-2 infection during pregnancy

Exposure to air pollution nanoparticles: depressive-like behaviors, learning and memory impairment and alters of hippocampal cytokines expression

HBK-15 preferentially activates ß-arrestin recruitment and GIRK channels after binding to the 5-HT1A receptor and reverses long-term memory impairments in mice

Hippocampal neurovascular coupling and spatial working memory impairment in a rodent model of type 2 diabetes: impact of dietary nitrate intervention

Hippocampal CB1 receptors control obesogenic diet-induced memory impairment

Mild liver damage induces spatial learning and memory impairment in rats. Underlying mechanisms and prevention by rifaximin

The role of inputs from hippocampus and entorhinal cortex to the prefrontal cortex in spatial memory impairments in a mouse model of Alzheimer's disease

A behavioural assessment to characterize different stages of memory impairment in humanized APP knock-in mouse models across various ages

FENS Forum 2024

Changes in neurotransmitter activity in septo-hippocampal network in naturally aged rats and a rat model of aging induced by D-galactose administration: Relationship with memory impairment

FENS Forum 2024

Hyperactivity, social deficits, and spatial working memory impairment in a new mouse model of 3-hit schizophrenia

FENS Forum 2024

Impact of hippocampal parvalbumin interneurons on memory impairment in rat models of Parkinson's disease

FENS Forum 2024

Performance in simple eye-tracking tasks indicates verbal memory impairments in epilepsy

FENS Forum 2024

Posterior parietal cortex oscillatory activity shapes persistent spatial memory impairments induced by soluble amyloid-β oligomers

FENS Forum 2024