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The mammalian forebrain is constructed from ensembles of neurons that form local microcircuits giving rise to the exquisite cognitive tasks the mammalian brain can perform. Hippocampal neuronal circuits comprise populations of relatively homogenous excitatory neurons, principal cells and exceedingly heterogeneous inhibitory neurons, the interneurons. Interneurons release GABA from their axon terminals and are capable of controlling excitability in every cellular compartment of principal cells and interneurons alike; thus, they provide a brake on excess activity, control the timing of neuronal discharge and provide modulation of synaptic transmission. The dendritic and axonal morphology of interneurons, as well as their afferent and efferent connections within hippocampal circuits, is central to their ability to differentially control excitability, in a cell-type- and compartment-specific manner. This review aims to provide an up-to-date compendium of described hippocampal interneuron subtypes, with respect to their morphology, connectivity, neurochemistry and physiology, a full understanding of which will in time help to explain the rich diversity of neuronal function.

The active electrical properties of dendrites shape neuronal input and output and are fundamental to brain function. However, our knowledge of active dendrites has been almost entirely acquired from studies of rodents. In this work, we investigated the dendrites of layer 2 and 3 (L2/3) pyramidal neurons of the human cerebral cortex ex vivo. In these neurons, we discovered a class of calcium-mediated dendritic action potentials (dCaAPs) whose waveform and effects on neuronal output have not been previously described. In contrast to typical all-or-none action potentials, dCaAPs were graded; their amplitudes were maximal for threshold-level stimuli but dampened for stronger stimuli. These dCaAPs enabled the dendrites of individual human neocortical pyramidal neurons to classify linearly nonseparable inputs—a computation conventionally thought to require multilayered networks.

Key Points Oscillatory activity in the gamma frequency range (30–90 Hz) is a hallmark of the function of the hippocampal network. These oscillations are thought to be important for information processing. Gamma oscillations can be replicated in in vitro models, in which the underlying mechanisms can be analysed systematically. In all in vitro models, gamma oscillations are dependent on GABA A (γ-aminobutyric acid type A)-receptor-mediated inhibition, suggesting that these oscillations are primarily generated by networks of inhibitory interneurons. Fast-spiking, parvalbumin-expressing basket cells are key components of the hippocampal interneuron network. They are extensively interconnected and fire action potentials that are phase-locked to the oscillations. Interneuron network models that are based on mutual inhibition, assuming slow, weak and hyperpolarizing synapses, generate synchronized gamma activity if exposed to a tonic excitatory drive. However, these models are highly sensitive to heterogeneity in the drive. Experimental analysis has revealed that basket cell–basket cell synapses are functionally specialized. They mediate fast, strong and shunting inhibition. Realistic interneuron network models generate synchronized gamma activity with increased robustness against heterogeneity in the tonic excitatory drive. Experimental analysis further reveals that basket cells are rapidly excited through gap junctions and fast glutamatergic synapses. Both gap junctions and fast glutamatergic synapses stabilize gamma activity in interneuron networks. Specialized synaptic properties turn the interneuron network into a robust gamma frequency oscillator. Therefore, interneuron networks might provide a precise reference signal for temporal encoding of information in principal neurons. Gamma oscillations have been implicated in higher brain functions, including memory formation, and may be disturbed in some psychiatric disorders. Jonas and colleagues describe the synaptic mechanisms by which gamma oscillations are generated in inhibitory interneuron networks in the hippocampus. Gamma frequency oscillations are thought to provide a temporal structure for information processing in the brain. They contribute to cognitive functions, such as memory formation and sensory processing, and are disturbed in some psychiatric disorders. Fast-spiking, parvalbumin-expressing, soma-inhibiting interneurons have a key role in the generation of these oscillations. Experimental analysis in the hippocampus and the neocortex reveals that synapses among these interneurons are highly specialized. Computational analysis further suggests that synaptic specialization turns interneuron networks into robust gamma frequency oscillators.

In this study, the temporal evolution of the cardiovascular response to sepsis was investigated by combining conventional hemodynamic parameters with novel indices derived from arterial blood pressure (ABP) waveforms that reflect vascular properties. The well-established association between sepsis and vascular dysfunction suggests that waveform-based indices may be instrumental in sepsis early detection and quantitative assessment of sepsis severity. ABP was continuously recorded at aortic and femoral sites in 40 pigs from a baseline condition to the full development of septic shock which was induced by intraperitoneal instillation of autologous feces. Standard beat-to-beat indices, including mean ABP, heart rate, and pulse pressure (PP), were computed alongside advanced cardiovascular markers such as baroreflex sensitivity, characteristic time constant ( ), PP amplification, and harmonic distortion (HD). Time series clustering was performed using a K-mean clustering approach with soft-dynamic time warping distance metric using 4 features - PP amplification, femoral , aortic systolic ABP, and femoral HD - selected by the First Integer Neighbor Clustering Hierarchy filtering method. According to the main physiological parameters typically evaluated by clinicians, all animals experienced severe cardiovascular decompensation under septic conditions. However, the time series cluster analysis identified two clusters with distinct temporal patterns of the cardiovascular variables. Shapelet analysis confirmed these findings, revealing consistent variable-specific trends. The proposed indices may assist clinicians in the early identification of sepsis and monitoring of sepsis severity, supporting more timely and personalized therapeutic strategies. Further studies are needed to explore their relationship with treatment response and clinical outcomes.

The brain of mammals lacks a significant ability to regenerate neurons and is thus particularly vulnerable. To protect the brain from injury and disease, damage control by astrocytes through astrogliosis and scar formation is vital. Here, we show that brain injury in mice triggers an immediate upregulation of the actin-binding protein Drebrin (DBN) in astrocytes, which is essential for scar formation and maintenance of astrocyte reactivity. In turn, DBN loss leads to defective astrocyte scar formation and excessive neurodegeneration following brain injuries. At the cellular level, we show that DBN switches actin homeostasis from ARP2/3-dependent arrays to microtubule-compatible scaffolds, facilitating the formation of RAB8-positive membrane tubules. This injury-specific RAB8 membrane compartment serves as hub for the trafficking of surface proteins involved in astrogliosis and adhesion mediators, such as β1-integrin. Our work shows that DBN-mediated membrane trafficking in astrocytes is an important neuroprotective mechanism following traumatic brain injury in mice. Reactive astrocytes control tissue damage following traumatic brain injury. Here the authors show that Drebrin (DBN) regulates scar formation and astrocyte reactivity in mice. Astrocytic DBN plays its neuroprotective role through the mediation of membrane trafficking.

[This corrects the article DOI: 10.1371/journal.pone.0260668.].

Developing food supply chains in the African agriculture could be one of the keys for higher value-added activities and for the fair income of the stakeholders along the chains. Our research aims to investigate how these agricultural value chains are working in Northern Ghana and how to develop them. To estimate meat demand in the Tamale Metropolis, we carried out a large-scale survey with more than 300 interviews. Furthermore, we also measured the awareness of processed meat products. Based on the results, our conclusions are as follows: Development of public services offers the opportunity to (1) gaining market power for ourselves while losing market power for others, (2) indirect takeover of control on political and civil societies while losing control for others, (3) to win allies and friends on one hand, potentially losing allies and friends on the other. After spatial analyses of grazing areas, animal markets, trading routes and witnessing the descriptions of basic macroeconomic differences within Ghana; we must conclude that live animal trade is south-orientated, where traders are able to bargain higher prices. Due to northern locational advantages, the price of animals could be reduced. The presumably cheaper workforce and dozens of unemployed young males could also alleviate the financial burdens.

The medial entorhinal cortex (mEC) plays a critical role for spatial navigation and memory. While many studies have investigated the principal neurons within the entorhinal cortex, much less is known about the inhibitory circuitries within this structure. Here, we describe for the first time in the mEC a subset of parvalbumin-positive (PV+) interneurons (INs)—stuttering cells (STUT)—with morphological, intrinsic electrophysiological, and synaptic properties distinct from fast-spiking PV+ INs. In contrast to the fast-spiking PV+ INs, the axon of the STUT INs also terminated in layer 3 and showed subthreshold membrane oscillations at gamma frequencies. Whereas the synaptic output of the STUT INs was only weakly reduced by a μ-opioid agonist, their inhibitory inputs were strongly suppressed. Given these properties, STUT are ideally suited to entrain gamma activity in the pyramidal cell population of the mEC. We propose that activation of the μ-opioid receptors decreases the GABA release from the PV+ INs onto the STUT, resulting in disinhibition of the STUT cell population and the consequent increase in network gamma power. We therefore suggest that the opioid system plays a critical role, mediated by STUT INs, in the neural signaling and oscillatory network activity within the mEC.

Even tough clitoris plays a critical role in female sexuality, we lack a precise understanding of qualitative and quantitative aspects of the innervation of the human clitoris. To address this issue, we dissected human clitorides from body donors and imaged them after staining with iodine with microCT for a macroscopic analysis. To resolve innervation patterns at the microscopic level we prepared thin sections of clitorides and stained them with trichrome azan to reveal the tissue structure combined with immunocytochemistry against Neurofilament H antibodies to reveal all axons and luxol blue labeling to reveal myelinated axons. We find the clitoral branch of pudendal nerve that innervates the clitoris not as single nerve, but as number of loose bundles. In the crus of the clitoris, about 12 such bundles can be recognized while about 32 bundles are present in the clitoral hemi-body. We counted on avarage 2917 axons in the crus of the clitoris (76% of which are myelinated) and 3137 axons in the hemibody of the clitoris (71% of which are myelinated). While the human clitoris receives only one third of the number of axons that innervate the human penis, an estimate of innervation density (per surface area) revealed that clitoris has approximately 6 times denser innervation compared to the penis. Thus, our study combines histology with microCT analysis provides detailed information on the number, myelination and innervation density of dorsal nerve of clitoris.

The original version of this article inadvertently presented a mistake regarding the termination zones of entorhinal cotex in the dentate gyrus. The termination zones were erroneously swapped in both Figure 7. and the associated text.