The functional significance of microglia found in neuritic plaques in Alzheimer's disease (AD) remains a source of controversy. In the present study, we explored the anatomic relationships between microglia and neuritic plaques in order to determine the potential role of microglia in plaque formation. We chose to study the molecular layer of the hippocampal dentate gyrus, a brain region where plaques have a strong tendency to line up parallel to the adjacent granule cell layer. We found that ferritin-labeled microglia were indeed most numerous in the same distinct band as plaques, but that microglia were relatively more common in the outer molecular layer. The distribution of microglia was more variable than that of plaques. Overall, microglial cell distribution was a relatively poor predictor of plaque distribution, particularly when cases were considered individually. Thus, there must be multiple triggers for microglial cell activation and accumulation in the AD brain, triggers which do not all necessarily lead to neuritic plaque formation.
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http://dx.doi.org/10.1097/00005072-199603000-00012 | DOI Listing |
Front Neural Circuits
January 2025
Department of Neurobiology, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
A strong repetitive stimulus can occasionally enhance axonal excitability, leading to the generation of afterdischarge. This afterdischarge outlasts the stimulus period and originates either from the physiological spike initiation site, typically the axon initial segment, or from ectopic sites for spike generation. One of the possible mechanisms underlying the stimulus-induced ectopic afterdischarge is the local depolarization due to accumulated potassium ions surrounding the axonal membranes of the distal portion.
View Article and Find Full Text PDFJ Physiol Sci
January 2025
Department of Integrative Neuroscience, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan. Electronic address:
Experiments measuring evoked potentials require flexible and rapid adjustment of stimulation and recording parameters. In this study, we have developed a recording system and an associated Android application that allow making such adjustments wirelessly. The system consists of 3 units: for stimulation, recording and control.
View Article and Find Full Text PDFNeurosci Lett
January 2025
Department of Pharmacology, School of Pharmacy, International University of Health and Welfare, 2600-1 Kitakanemaru, Ohtawara, Tochigi 324-8501, Japan. Electronic address:
Disruption of gut microbiota balance is known to contribute to the development of anxiety; however, it remains unclear whether dysbiosis-induced anxiety involves the glycogen synthase kinase-3β (GSK-3β)/cAMP response element binding protein (CREB)/brain-derived neurotrophic factor (BDNF) pathway and neurogenesis in the ventral hippocampal dentate gyrus (DG). In this study, Male ddY mice were administered an antibacterial cocktail to induce dysbiosis. The dysbiosis model displayed anxiety-like behaviors in the hole-board and elevated plus-maze tests, decreased the phosphorylation levels of GSK-3β (Ser9) and CREB, decreased the expression level of BDNF in the ventral hippocampus, and reduced neurogenesis in the ventral hippocampal DG.
View Article and Find Full Text PDFBehav Brain Res
January 2025
Laboratorio de Neurobiología, División de Biología Molecular, Instituto Potosino de Investigación Científica y Tecnológica (IPICYT), San Luis Potosí, Mexico. Electronic address:
Ketamine hydrochloride serves multiple purposes, including its use as a general anesthetic, treatment for depression, and recreational drug. In studies involving rodents, ketamine is utilized as a model for schizophrenia. However, it is unclear whether age affects the behavioral response induced by repeated ketamine administration and if it modifies the expression levels of N-methyl-D-aspartate (NMDA) and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and purinergic receptors (P2X1, P2X4, P2X7).
View Article and Find Full Text PDFBiol Psychiatry Glob Open Sci
March 2025
Department of Psychiatry, Division of Systems Neuroscience, Columbia University, New York State Psychiatric Institute, New York, New York.
Background: Impairments in behavioral pattern separation (BPS)-the ability to distinguish between similar contexts or experiences-contribute to memory interference and overgeneralization seen in many neuropsychiatric conditions, including depression, anxiety, posttraumatic stress disorder, dementia, and age-related cognitive decline. Although BPS relies on the dentate gyrus and is sensitive to changes in adult hippocampal neurogenesis, its significance as a pharmacological target has not been tested.
Methods: In this study, we applied a human neural stem cell high-throughput screening cascade to identify compounds that increase human neurogenesis.
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