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Research on neuronal connectivity in the cerebral cortex has focused on the existence and strength of synapses between neurons, and their location on the cell bodies and dendrites of postsynaptic neurons. The synaptic architecture of individual presynaptic axonal trees, however, remains largely unknown. Here we used dense reconstructions from three-dimensional electron microscopy in rats to study the synaptic organization of local presynaptic axons in layer 2 of the medial entorhinal cortex, the site of grid-like spatial representations. We observe path-length-dependent axonal synapse sorting, such that axons of excitatory neurons sequentially target inhibitory neurons followed by excitatory neurons. Connectivity analysis revealed a cellular feedforward inhibition circuit involving wide, myelinated inhibitory axons and dendritic synapse clustering. Simulations show that this high-precision circuit can control the propagation of synchronized activity in the medial entorhinal cortex, which is known for temporally precise discharges.
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http://dx.doi.org/10.1038/nature24005 | DOI Listing |
Individual differences in neural circuits underlying emotional regulation, motivation, and decision-making are implicated in many psychiatric illnesses. Interindividual variability in these circuits may manifest, at least in part, as individual differences in impulsivity at both normative and clinically significant levels. Impulsivity reflects a tendency towards rapid, unplanned reactions to internal or external stimuli without considering potential negative consequences coupled with difficulty inhibiting responses.
View Article and Find Full Text PDFStudy Objectives: Brief sleep loss alters cognition and the activity and synaptic structures of both principal neurons and interneurons in hippocampus. However, although sleep-dependent coordination of activity between hippocampus and neocortex is essential for memory consolidation, much less is known about how sleep loss affects neocortical input to hippocampus, or excitatory-inhibitory balance within neocortical structures. We aimed to test how the synaptic structures of SST+ interneurons in lateral and medial entorhinal cortex (LEC and MEC), which are the major neocortical input to hippocampus, are affected by brief sleep disruption in the hours following learning.
View Article and Find Full Text PDFBackground: One of the most persistent questions in autism research is why males are more consistently diagnosed than females. Neuroimaging studies have sought to understand this disparity by examining sex differences, primarily through functional and structural connectivity. However, much less is known about how brain networks are organized in autism from a morphological perspective, and how this organization may help explain its sex-related characteristics.
View Article and Find Full Text PDFFront Neuroanat
August 2025
Department of Anatomy, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates.
Introduction: The gut microbiota plays a critical role in regulating brain structure and function via the microbiota-gut-brain axis. Antibiotic-induced gut dysbiosis (AIGD) has been linked to neuroanatomical changes and cognitive deficits. However, its impact on neuronal morphology in layer II of the medial entorhinal cortex (mECII), a region central to spatial memory, remains poorly understood.
View Article and Find Full Text PDFBrain Sci
August 2025
College of Information Engineering, Chinese People's Armed Police Force Engineering University, Xi'an 710086, China.
In recent years, complexity analysis has attracted considerable attention in the field of neural mechanism exploration due to its nonlinear characteristics, providing a new perspective for revealing the complex information processing mechanisms of the brain. In precision sports such as shooting, complexity analysis can quantify the complexity of activity in different areas of the brain and dynamic changes. This study extracted multiple complexity indicators based on microstate and traceability analysis and examined brain complexity during the shooting preparation stage and the brain's reaction mechanisms under audiovisual limitations.
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