Innervation pattern of dopaminergic and serotoninergic neurons in the adult wild-type Drosophila central brain. (A) Anti-5-HT (1) and anti-TH (2) immunoreactive neurons show to some degree complementary innervation patterns in the Drosophila brain. 5-HT-producing neurons strongly innervate the AL (A) and only weakly the MBs (B1,2). TH-positive neurons innervate only the outer rim of the AL (A2,3), but strongly the mushroom body (MB) (B1,2). The tips of the α’ lobes are innervated by both populations of aminergic neurons (B1–2). Innervation pattern of 5-HT neurons and dopamine (DA) neurons in the ellipsoid body (C1,2, EB) and the fan-shaped body (D1–2, FB). 5-HT-producing neurons innervate strongly the inner rim of the EB (C1,2) and the dorsal part of the FB (D1,2). DA-producing neurons innervate strongly the outer rim of the EB (C1,2) and the ventral part of the FB (D1,2). The protocerebral bridge (PB) is innervated by DA, but by 5-HT producing neurons (E1,2). 3D reconstruction of the MB (B1), EB (C1), the FB (D1) and the PB (E1) with DA and 5-HT IR indicated in different colors (D, dorsal; L, lateral; P, posterior; A, anterior). Scale bars: 50 μm.