Interestingly, the variations of our behavioral data seemed to be tightly correlated to decreased expression of TrkB in the cerebellum, brain site that is known to be, via reciprocal connections with the prefrontal cortex, not only a key motor controlling site but recently has been also shown to influence appetite signals in obesity conditions [44]. The gene discussed is NTRK2; the disease is obesity due to melanocortin 4 receptor deficiency.