Figure 5.

5-HT neurons projecting to the MB show altered innervation densities in DA-deficient flies. (A) Innervation patterns of 5-HT neurons to the α/α’-lobe of the MB. Under wild-type conditions, 5-HT producing neurons innervate strongly the tips of the α’ but only faintly the α lobes. In DA-deficient flies, 5-HT innervations to the α lobes are markedly increased. Scale bar: 10 μm (B) Fluorescence intensity analysis of the 5-HT IR in α– and α’-lobes. 5-HT innervations to the α-lobes are increased in flies lacking neuronal TH when compared to control flies. (C) Ratio of 5-HT innervation density between α’- and α-lobes. Under control conditions, 5-HT neurons innervate α’-lobes stronger than the α lobes. In DA-deficient flies, 5-HT-neuron α-lobe innervations are increased and comparable to the α’-lobe innervations. (D) The surface of the α/α’-lobes that are targeted by 5-HT neurons is not altered between DA-deficient and control flies (Dunn’s multiple comparison test against w¹¹¹⁸, n < 13). n.s.: p > 0.05; ***p < 0.001.