Interestingly, overexpression of extracellular HMGB1 has been observed in clinical and preclinical studies on Parkinson's disease (10), stroke (11), traumatic brain injury (12), epilepsy (13), autism (14), depression (15), multiple sclerosis (16), and amyotrophic lateral sclerosis (17). Here, HMGB1 is linked to depressive symptom measurement.