We studied long-term potentiation in the inbred mouse strains DBA/2 and C3H/He known to be different in both hippocampal mossy fiber distribution and several aspects of learning. Tetanic stimulation of mossy fibers resulted in a significantly stronger increase of the population spike amplitude in the CA3 pyramidal cell layer of C3H mice. This result suggests that the extent of the CA3 hippocampal mossy fiber projection correlates with synaptic efficacy in mice.
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http://dx.doi.org/10.1016/0006-8993(89)90262-x | DOI Listing |
The hippocampus forms memories of our experiences by registering processed sensory information in coactive populations of excitatory principal cells or ensembles. Fast-spiking parvalbumin-expressing inhibitory neurons (PV INs) in the dentate gyrus (DG)-CA3/CA2 circuit contribute to memory encoding by exerting precise temporal control of excitatory principal cell activity through mossy fiber-dependent feed-forward inhibition. PV INs respond to input-specific information by coordinating changes in their intrinsic excitability, input-output synaptic-connectivity, synaptic-physiology and synaptic-plasticity, referred to here as experience-dependent PV IN plasticity, to influence hippocampal functions.
View Article and Find Full Text PDFFront 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 PDFEur J Neurosci
January 2025
Université Grenoble Alpes, CNRS, LIPhy, Grenoble, France.
Staining brain slices with acetoxymethyl ester (AM) Ca dyes is a straightforward procedure to load multiple cells, and Fluo-4 is a commonly used high-affinity indicator due to its very large dynamic range. It has been shown that this dye preferentially stains glial cells, providing slow and large Ca transients, but it is questionable whether and at which temporal resolution it can also report Ca transients from neuronal cells. Here, by electrically stimulating mouse hippocampal slices, we resolved fast neuronal signals corresponding to 1%-3% maximal fluorescence changes.
View Article and Find Full Text PDFBiomedicines
December 2024
Department of Neurosurgery, Freiburg University Medical Center, Breisacher Str. 64, 79106 Freiburg, Germany.
Background: Temporal lobe epilepsy (TLE) is the most common form of drug-resistant epilepsy, often associated with hippocampal sclerosis (HS), which involves selective neuronal loss in the Cornu Ammonis subregion 1 CA1 and CA4 regions of the hippocampus. Granule cells show migration and mossy fiber sprouting, though the mechanisms remain unclear. Microglia play a role in neurogenesis and synaptic modulation, suggesting they may contribute to epilepsy.
View Article and Find Full Text PDFBehav Brain Res
March 2025
Departament de Biologia, Universitat de Girona, Girona, Spain. Electronic address:
Background: Post-traumatic stress disorder (PTSD) causes intrusive symptoms and avoidance behaviours due to dysregulation in various brain regions, including the hippocampus. Deep brain stimulation (DBS) shows promise for refractory PTSD cases. In rodents, DBS improves fear extinction and reduces anxiety-like behaviours, but its effects on active-avoidance extinction remain unexplored.
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