changes in striatal gene expression. Similarly, we observed enrichment of synaptic transcripts when looking specifically at genes in the caudate that differed in the same direction between subject groups in the two studies, (Fig. S6 and Table S10). A key difference between our findings and those of Lisboa et al. is that our analyses did not reveal any group difference in immune- or microglia-related gene sets. There are many possible explanations for this, including the age of subjects (age-range 58–98 in Lisboa et al.37, age-range 20–69 in the current work), as aging is associated with changes in immune system gene expression62. The role of the immune system in OCD (and its interaction with age and disease length) requires further study.
