Pyramidal cells

The hippocampus is a key player in learning and memory. However, the microcircuit logic that endows the hippocampus with these capabilities remains virtually unknown. Hippocampal neurons exhibit tremendous diversity in terms of their gene expression, connectivity, and intrinsic properties. Recent work suggests that this diversity is rooted in the temporal progression of embryonic development, with neurons born at the same gestational timepoint exhibiting shared input and output connectivity, as well as correlated activity in-vivo. In this work, we combined embryonic birthdating of CA3-CA1 neur

…Pyramidal cells are thought to be the main sites to perform this integration locally. Signals from the two different pathways are integrated at distinct sites of the pyramidal cell [2]. Information originating up-stream, closer to primary sensory input, is integrated at basal peri-somatic dendrites and drives the cell's firing. Contextual information from down-stream sources is integrated at distal apical dendrites and amplifies the cell's firing only if coinciding with basal input. Importa

…expressed hM4Di for silencing pyramidal cells in the hippocampus of neonatal mice. Electrophysiological recordings from CA1 pyramidal cells demonstrate that hM4Di does not mediate hyperpolarization or shunting and, i

Electrical activity plays a crucial role in the development of neurons and the formation of neuronal networks. Designer receptors exclusively activated by designer drugs (DREADDs) are chemogenetic tools that can control the activity of neurons at the single-cell level by activating specific G protein signaling. In this study, we aimed to investigate whether the excitatory hM3Dq receptor is sufficient to influence the growth of dendrites and axons in cortical neurons. When activated, Gq-coupled hM3Dq leads to depolarization by increasing intracellular calcium levels. We biolistically transfecte

…properties of synapses between pyramidal cells depend on the hemispheric origin of presynaptic inputs. In the CA3-CA1 connection, right-input synapses in stratum radiatum have larger postsynaptic density (PSD) and higher perforation ratio, expressing lower NR2B subunit density, than left-input synapses. The major histocompatibility complex class I (MHCI) and Paired immunoglobulin-like receptor B (PirB) contribute to this asymmetry, suggesting potential trans-synaptic signal

…neuronal classes in the PL, including pyramidal cells (Pyr), parvalbumin- (PV+), somatostatin- (Sst+), and vasoactive intestinal peptide- (VIP+) expressing interneurons, in processing information about familiar and novel social stimuli.We employed chemo/optogenetics alongside automated behavioral testing in Eco-HAB®, an RFID-based system for ecologically relevant assessment of social behavior in group-housed mice. This

Early life stress (ELS) is one of the key risk factors in the development of mental health disorders, strongly impacting the limbic system. Kainate receptors and GluK1 specifically have been previously shown to be affected, and potentially mediate some of the effects of ELS on GABAergic interneurons. Aims: To study the effects of the ELS on the circuitry of the ventral hippocampus (vHPC) and assess the potential of GluK1 as a tool for phenotype rescue.Methods: Limited bedding and nesting model of ELS was used in WT and PV-Cre mice and validated using standard behavioral tests in adults. Electr

…Pyramidal cells are the principal cell type in the subiculum and based on their firing dynamics, they can be divided into regular and bursting phenotypes. Previously, functional characterization of these cells was mainly performed by using conventional electrophysiological methods (current steps). However, our research group uses advanced methods (dynamic clamp) to expose neurons to physiolog

…of NVC, cyclooxygenase-2 (COX2) pyramidal cells, play a key role via the release of prostaglandin E2 (PGE2), which can bidirectionally control the NVC. We investigated the role of pyramidal cells in neurovascular uncoupling of AD using cortical slices from triple transgenic mice expres

The function of the cerebral cortex relies on the cellular balance between excitatory (pyramidal cells) and inhibitory neurons (interneurons), which is disrupted in disorders such as autism or schizophrenia. The emergence of cortical function during postnatal development relies on spontaneous synchronous activity among large groups of pyramidal cells and interneurons, which later desynchronise for efficient information processing. Before this network activity shift, interneuron numbers are adjusted through activity-dependent programmed cell death mechanisms. However, the extent to which the ad

Exaggerated responses to sensory stimuli is a hallmark of Fragile X syndrome (FXS), contributes to, inattention, anxiety, and learning challenges. Such sensory hypersensitivity are recapitulated in the Fmr1 knockout (KO). Recent studies in Fmr1 KO mice have demonstrated differences in GABAergic inhibition, including activity of cortical interneurons as well as a delayed switch in the polarity of GABA signaling during development. Previously, we found that administration of bumetanide to block the chloride (Cl-) transporter NKCC1, could rescue synaptic circuit phenotypes in primary somatosensor

…Excitatory cells play a similar instructi

We present a 3D multi-shank linear electrode array for semichronic laminar neural recording in drug-resistant epilepsy patients. The 3D array comprises nine parallel shanks (3x3, lateral spacing: 1 mm) fixed on a 4.5x4.5 mm PEEK platform. An individual shank (185 μm OD) has a conical-shaped taper and contains 16 or 24 recording sites (15 μm OD microwires, Pt/Ir–90/10%; inter-site distances may vary between 50–200 μm). The microwires provide an uninterrupted connection between the recording sites and a PCB with Omnetics connectors for headstage input. The 3D array allows for easy and quick oper

One of the main targets of the vesicular glutamate transporter type 3 (vGluT3)-expressing median raphe neurons, is the dorsal hippocampus, a key node of the brain’s episodic memory circuit. We uncovered previously that the raphe-hippocampal glutamatergic connection selectively and highly efficiently activates certain types of hippocampal inhibitory neurons at very short latency. However, the function of this powerful inhibition-targeting modulation is still elusive. In this study, we combined the selective tagging of either vGluT3 MR neurons or their hippocampus-projecting subgroup and high-de

…effects of optogenetic excitation of pyramidal cells in V1 of mice and mon

…layer 1, which houses the dendrites of pyramidal cells (PC; Schuman et al., 2021). While layer 1 is devoid of excitatory cell bodies, it contains a variety of interneurons, including neurogliaform cells expressing neuron-derived neurotrophic factor (NDNF; Abs et al., 2018). NDNF interneurons are unique in that they provide slow inhibition, partially via non-synaptic volume release of GABA (Pardi et al. 2020). Yet, their co

…Because pyramidal cells in CA1 do not have local recurrent projections, it is currently assumed that firing in CA1 is inherited from its inputs – thus, entorhinal inputs provide communication with the rest of the neocortex and the outside world, whereas CA3 inputs provide internal and past memory representations. Several studies have attempted to prove this hypothesis, by lesioning or silencing either area CA3 or the entorhinal cortex and examinin

Hippocampal networks link temporally contiguous memories through spiking sequences that encode sensory cues (external world) and time between them (internal representations), constructing ‘memory-maps’ of related experiences. It was recently shown that such sequences combine particularly stable representations of sensory cues with highly dynamic, learning- dependent temporal-codes. This combination of stability and flexibility allows linking fixed elements of the external world across variable time intervals. But how does feedback inhibition by parvalbumin- (PV) and somatostatin-expressing (SO

…Specifically, the subset of cells which are active on any given session in a familiar environment changes over the course of days and weeks. While some cells transition into or out of the code after a few sessions, others are stable over the entire experiment. The mechanisms underlying this turnover are unknown. Here we show that the statistics of turnover are consistent with a model in which non-spatial inputs to CA1 pyramidal cells readily undergo p

There is little consensus on the level of spatial complexity at which dendrites operate. On the one hand, emergent evidence indicates that synapses cluster at micrometer spatial scales. On the other hand, most modelling and network studies ignore dendrites altogether. This dichotomy raises an urgent question: what is the smallest relevant spatial scale for understanding dendritic computation? We have developed a method to construct compartmental models at any level of spatial complexity. Through carefully chosen parameter fits, solvable in the least-squares sense, we obtain accurate reduced co

…a single synaptic interface: between pyramidal cells and putative interneurons. Using arbitrary white noise patterns injected intra-cortically as photocurrents to freely-moving mice, we find that directly-activated cells exhibit precisi