BDNF and obesity due to melanocortin 4 receptor deficiency: Given that obesity, poor cognitive performance, and their interrelationships are strongly associated with low BDNF18, 19, 20 and exercise training could improve cognition via BDNF enhancement among people with overweight and obesity,21, 22, 23 it is strongly believed that the major contributor accounting for the cognitive benefits of exercise training in obesity could be linked to enhancement of BDNF expression.