Examing how MPO activity in thalamus and cortex regions changed from naïve (pre-stroke), day 3 (post-stroke), and day 10 (post-stroke) brains in aged and young adults, we found that while aging primarily impacts the thalamus and spares the cortex in naïve mice with elevated MPO activity, MPO activity increased in both thalamus and cortex regions after stroke regardless of age (Supplementary Fig. 2). Here, MPO is linked to stroke disorder.