Cerebellum was dissected and nuclei were isolated. ATAC-seq libraries were prepared as described previously (Buenrostro et al., 2013; 2015) with the following modifications: nuclei were resuspended in ice-cold lysis buffer, omitting incubation step on ice and centrifuged. Transposition reaction was performed for 30 min at 37°C using Tn5 transposase from Nextera. DNA fragments were purified and size selected using AMPure XP beads to yield 100-700bp fragments. Libraries were generated using the Nextera DNA Library Preparation Kit. ATAC-seq libraries were sequenced on Illumina NextSeq 500 to obtain 75bp paired-ended reads.