Medical Student Charles E. Schmidt College of Medicine–FAU Boca Raton, Florida, United States
Introduction: Focused ultrasound and Gamma Knife radiosurgery have emerged as minimally invasive approaches for treating neurological conditions. However, their impact on both synaptic integrity and the structural components of the cortex remains largely unexplored. An understanding of their effects on synapses and cortical structures may lead to further improvements in the accuracy of these techniques. In the present study, the authors aim to demonstrate how data from a small segment of the human cortex can be used to assess its synaptic density and cortical integrity.
Methods: A high-resolution voxel sample (8x8x33 nm) of human temporal cortex tissue was obtained from the Harvard H01 database. Synapse segmentation data, generated through high-throughput serial section electron microscopy, was analyzed from cortical layer C3 using computer vision image segmentation algorithms in Python 3.8.0 (Python Software Foundation, Wilmington, DE). Each voxel of the 3D synapse segmentation data was assigned a unique segmentation ID and the total number of synapses in the ROI was calculated. A separate segment from the same sample (8x8x33nm) was used for cortical layer segmentation analysis.
Results: N=36,053 distinct synapses were identified within the extracted ROI from the C3 cortical layer. The physical volume of the ROI was calculated to be 269.72 µm³, resulting in a synapse density of 133.67 synapses/µm³. Analysis of 12 unique cortical components found: mean cortical volume=4.40 µm³, median=0.44 µm³, mode=38.02 µm³, and range=0.004178 µm³ to 38.02 µm³.
Conclusion : The present study utilizes high-resolution segmentation data to quantify both synaptic density and cortical component sizes. The use of this technique on brain tissue before and after radiation therapy may be an avenue to understand the effect of radiation on brain tissue and improve precision of delivery to minimize functional tissue loss.
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