This dataset is a spatially contiguous subset of the publicly available CosMx Spatial Molecular Imager (SMI) Mouse Brain FFPE dataset provided by NanoString Technologies (https://nanostring.com/products/cosmx-spatial-molecular-imager/ffpe-dataset/cosmx-smi-mouse-brain-ffpe-dataset/). A 500 × 500 µm region of interest was extracted from the original dataset to provide a compact, ready-to-use example dataset for demonstrating the SCRIN workflow. The spatial coordinates have been converted from pixels to micrometers. The preserved spatial continuity allows users to perform the main colocalization analysis and explore representative downstream analyses, including RNA distance-distribution visualization and tissue-level projection of colocalization events. This version replaces the previously provided dataset of 1,000 randomly sampled cells. Please refer to the original NanoString dataset for the complete data. Users of this example dataset should cite or acknowledge NanoString Technologies and the original data source as appropriate.