During the fourth session, neither latency to attack (Figure 3A), nor number of attacks (Figure 3B) were affected by 5-HT deficiency, MS or a Tph2∗MS interaction A significant difference between genotypes, attacking the belly during the fourth session [χ(2) = 16.7, p = 0.023] was observed, with 95% of the Tph2-/- mice targeting this body part at least once, while of Tph2+/- mice 55% and of Tph2+/+ mice 28% attacked the belly (Figure 3D). The gene discussed is TPH2; the disease is myeloid sarcoma.