Figure 7

Schematic drawing of the serotonin immunoreactivity in the brain of Speleonectes tulumensis. In the left hemisphere, 117 5HT-ir neurons were detected; in the right hemisphere, 116. These neurons are arranged in distinct cell groups (sA1, sA2, sB1, sB2, sD1, sD2, sE1, sE2) within the surrounding neuronal soma clusters (grey). Neurite bundles of these 5HT-ir neurons extend into the neuropil (white) and innervate distinct neuropilar domains (sd1-9; sd11-15) in different brain areas. In the olfactory lobes (ONs), only few olfactory glomeruli (GLOs) are exemplified. Projections from protocerebral cell groups are colored in red (sA1) and blue (sA2, sB1, sB2) for better discrimination between projections of these neurons. For the same reason, the 5HT-ir domains sd10 and sd16 are omitted. Abbreviations: A1Nv: antenna 1 nerve; GLO: olfactory glomerulus; HE: hemiellipsoid body; ON: olfactory neuropil; sA1, sA2, sB1, sB2, sD1, sD2, sE1, sE2: 5HT-ir cell groups; sd1-9, sd11-15: 5HT-ir domains.