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Connectomics allows mapping of cells and their circuits at the nanometer scale in volumes of approximately 1 mm. Given that the human cerebral cortex can be 3 mm in thickness, larger volumes are required. Larger-volume circuit reconstructions of human brain are limited by 1) the availability of fresh biopsies; 2) the need for excellent preservation of ultrastructure, including extracellular space; and 3) the requirement of uniform staining throughout the sample, among other technical challenges. Cerebral cortical samples from neurosurgical patients are available owing to lead placement for deep brain stimulation. Described here is an immersion fixation, heavy metal staining, and tissue processing method that consistently provides excellent ultrastructure throughout human and rodent surgical brain samples of volumes 2 × 2 × 2 mm and up to 37 mm with one dimension ≤2 mm. This method should allow synapse-level circuit analysis in samples from patients with psychiatric and neurologic disorders.
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http://dx.doi.org/10.1016/j.biopsych.2023.01.025 | DOI Listing |
eNeuro
September 2025
Institute of Cognitive Science, University of Osnabrück, Osnabrück 49090, Germany.
Current research strives to investigate cognitive processes under natural conditions. Virtual reality and EEG are promising techniques combining naturalistic settings with close experimental control. However, many questions and technical challenges remain, e.
View Article and Find Full Text PDFActa Biomater
August 2025
School of Material Science and Engineering, Zhengzhou University, Zhengzhou, 450001, China; Henan Key Laboratory of Advanced Light Alloys, Zhengzhou 450002, China; Zhongyuan Critical Metals Laboratory, Zhengzhou 450001, China. Electronic address:
Biodegradable magnesium alloys suture anchors face rapid anchor eyelet degradation, compromising mechanical strength. In this study, an assembled-structure magnesium alloy suture anchor was proposed to mitigate the fast failure of anchor eyelet. In vitro and in vivo experiments were conducted to evaluate the degradation behavior and biomechanical performance of assembled ZE21C magnesium alloy suture anchors.
View Article and Find Full Text PDFAnat Sci Int
August 2025
Department of Morphological Sciences, Graduate School of Medical and Dental Sciences, Kagoshima University, 8-35-1 Sakuragaoka, Kagoshima, 890-8544, Japan.
In the context of cell morphological analyses observing organelles embedded within the cell matrix is difficult. The osmium maceration method is a unique technique used to directly observe the three-dimensional structure of organelles through scanning electron microscopy, without requiring time-consuming and labor-intensive reconstruction. In this method, tissues are immersed in a diluted osmium solution for several days to remove cytosolic soluble proteins and filamentous structures, including microfilaments, intermediate filaments, and microtubules, from the freeze-cracked surfaces of cells, leaving the subcellular structures, Golgi apparatus, mitochondria, and smooth and rough endoplasmic reticulum intact.
View Article and Find Full Text PDFCureus
June 2025
Neurosurgery, Peoples' Friendship University of Russia, Moscow, RUS.
As part of a microsurgical anatomy study of the recurrent artery of Heubner (RAH), we identified three rare vascular variants in a 45-year-old female cadaver: the right middle accessory cerebral artery (MACA), bihemispheric anterior cerebral artery (Bihem-ACA), and median artery of the corpus callosum (MACC). These anomalies were documented through meticulous dissection and detailed morphometric analysis, underscoring the value of cadaveric studies in elucidating complex cerebral vascular anatomy. The specimen was obtained within 24 hours postmortem.
View Article and Find Full Text PDFDent Traumatol
July 2025
School of Stomatology, Southwest Medical University, Luzhou, China.
Background: This study evaluates novel osteotomy guides, a morphology-adapted custom drill, and root-immersion containers to enhance the precision in dental autotransplantation through in vitro experiments and finite element analysis (FEA).
Methods: About 30 mandibular Cone Beam Computed Tomography (CBCT) datasets were reconstructed to design reverse-engineered osteotomy guides and a steel custom drill based on root morphology statistics. About 90 3D-printed models (30 cases × 3 groups: guide-assisted, custom drill, and freehand) underwent socket preparation, with operative time and cavity dimensions quantified via optical scanning.