Hippocampal area CA2 is emerging as a critical region for memory formation. Excitatory Scaffer collateral (SC) inputs from CA3 do not express activity-dependent plasticity at SC-CA2 synapses, and are governed by a large feed-forward inhibition that prevents them from engaging CA2 pyramidal neurons. However, long-term depression at inhibitory synapses evoked by stimulation of SC inputs highly increases the excitatory/inhibitory balance coming from CA3 and allows the recruitment of CA2 pyramidal neurons. In contrast, distal excitatory inputs in stratum lacunosum moleculare (SLM) can drive action potential firing in CA2 pyramidal neurons and also express a long-term potentiation. However, it is unknown whether stimulation of distal inputs can also evoke plasticity at inhibitory synapses and if so, whether this plasticity can control the strength of excitatory inputs. Here we show that stimulation in SLM evokes a long-term depression at inhibitory synapses. This plasticity strongly increases the excitatory drive of both proximal and distal inputs and allows CA3 to recruit CA2 pyramidal neurons. These data reveal a bi-directional interplay between proximal and distal inputs to CA2 pyramidal neurons that is likely to play an important role in information transfer through the hippocampus.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1016/j.nlm.2016.06.024 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Neuronal Imaging at 8-Bit Depth to Combine High Spatial and High Temporal Resolution With Acquisition Rates Up To 40 kHz.
J Biophotonics
January 2025
Univ. Grenoble Alpes, CNRS, LIPhy, Grenoble, France.
A challenge in neuroimaging is acquiring frame sequences at high temporal resolution from the largest possible number of pixels. Measuring 1%-10% fluorescence changes normally requires 12-bit or higher bit depth, constraining the frame size allowing imaging in the kHz range. We resolved Ca or membrane potential signals from cell populations or single neurons in brain slices by acquiring fluorescence at 8-bit depth and by binning pixels offline, achieving unprecedented frame sizes at kHz rates.
View Article and Find Full Text PDFPerineuronal nets on CA2 pyramidal cells and parvalbumin-expressing cells differentially regulate hippocampal dependent memory.
J Neurosci
December 2024
Neurobiology Laboratory, National Institute of Environmental Health Sciences, Division of Intramural Research, National Institute of Health, Research Triangle Park, North Carolina 27713, USA
Perineuronal nets (PNNs) are a specialized extracellular matrix that surround certain populations of neurons, including (inhibitory) parvalbumin (PV) expressing-interneurons throughout the brain and (excitatory) CA2 pyramidal neurons in hippocampus. PNNs are thought to regulate synaptic plasticity by stabilizing synapses and as such, could regulate learning and memory. Most often, PNN functions are queried using enzymatic degradation with chondroitinase, but that approach does not differentiate PNNs on CA2 neurons from those on adjacent PV cells.
View Article and Find Full Text PDFProtective effect of sub-hypothermic mechanical perfusion combined with membrane lung oxygenation on a yorkshire model of brain injury after traumatic blood loss.
Chin J Traumatol
December 2024
Beijing Key Lab of Regenerative Medicine in Orthopedics, Key Laboratory of Musculoskeletal Trauma and War Injuries PLA, Department of Orthopedics, The Fourth Medical Center, Chinese PLA General Hospital, Beijing, 100048, China. Electronic address:
Purpose: To investigate the protective effect of sub-hypothermic mechanical perfusion combined with membrane lung oxygenation on ischemic hypoxic injury of yorkshire brain tissue caused by traumatic blood loss.
Methods: This article performed a random controlled trial. Brain tissue of 7 yorkshire was selected and divided into the sub-low temperature anterograde machine perfusion group (n = 4) and the blank control group (n = 3) using the random number table method.
Co-pathologies modify hippocampal protein accumulation patterns in neurodegenerative diseases.
Alzheimers Dement
December 2024
Department of Laboratory Medicine and Pathobiology and Department of Medicine, University of Toronto, Toronto, Ontario, Canada.
Introduction: Limited research has extensively analyzed neurodegenerative disease-related protein deposition patterns in the hippocampus.
Methods: This study examined the distribution of proteins in hippocampal subregions across major neurodegenerative diseases and explored their relation to each other. The area density of phosphorylated tau (p-tau), amyloid beta (Aβ), α-synuclein, and phosphorylated TDP-43 protein deposits together with pyramidal cell density in each hippocampal subregion, including CA1-4, prosubiculum (ProS), and subiculum was assessed in 166 cases encompassing various neurodegenerative diseases.
Effects of dendritic Ca spike on the modulation of spike timing with transcranial direct current stimulation in cortical pyramidal neurons.
J Comput Neurosci
December 2024
School of Electrical and Information Engineering, Tianjin University, Tianjin, 300072, China.
Transcranial direct current stimulation (tDCS) generates a weak electric field (EF) within the brain, which induces opposite polarization in the soma and distal dendrite of cortical pyramidal neurons. The somatic polarization directly affects the spike timing, and dendritic polarization modulates the synaptically evoked dendritic activities. Ca spike, the most dramatic dendritic activity, is crucial for synaptic integration and top-down signal transmission, thereby indirectly influencing the output spikes of pyramidal cells.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!