CREB1 and Parkinson disease: Specifically, in midbrain neurons of PD patients, the pathway regulating peroxisome proliferator-activated receptor-gamma coactivator (PGC-1α), a transcriptional coactivator involved in mitochondrial processes, stress-induced apoptosis, and cAMP response element-binding protein (CREB) function, is inactivated, indicating mitochondrial dysfunction and another potential source of oxidative stress in PD (Liu and Lin, 2011; Schulze et al., 2018).