title: GSM9377975: V303-CGND-HRA-03648-C; Homo sapiens; OTHER
library_construction_protocol: Frozen tissue blocks, kept at -80°C prior to processing, were equilibrated to -16°C inside a Leica CM3050S cryostat, embedded in Tissue Plus OCT Compound (Fisher Healthcare, #4585), and sectioned in a perpendicular orientation with regard to the pial surface. Tissue sections (10 µm-thick) from quality controlled blocks (H&E staining and imaging) were collected onto prechilled Visium Spatial Gene Expression Slides (10X Genomics, #1000185) while briefly warming the back of the slide with a gloved finger to improve adherence and minimize artifacts. We sought to capture cortical layers 1 through 6 and white matter within each spatially barcoded array. Visium libraries were prepared using unique Illumina-compatible PCR primers with Dual Index Kit TT Set A (10X Genomics, #1000215). Size distribution profiles of the final libraries were assessed by running Agilent High Sensitivity DNA chips (#5067-4626) on a 2100 Bioanalyzer system (Agilent, #G2939BA). Libraries outside the expected range (450 ± 50 bp) or that contained adapter dimer contaminants were discarded and reprocessed. Total yields were initially measured on a Qubit 3.0 fluorometer before final qPCR quantification (KAPA Library Quantification Kit for Illumina Platforms, KAPA Biosystems, #KK4824).