In contrast, the hippocampus showed a distinct pattern: expression of TNF-α and IL-1β changed very little across diets or treatments, whereas IL-6 and CCL2 were selectively altered by L-alliin, depending on the animals' metabolic state.<h4>Conclusions</h4>These findings demonstrate that diet-induced obesity does not affect the entire brain uniformly. The gene discussed is CCL2; the disease is obesity due to melanocortin 4 receptor deficiency.