Confocal photomicrographs (maximum projections) of transverse sections of a shh-GFP zebrafish cerebellum at 5 dpf (A–C) and sections of a wild-type adult brain immunostained for Zebrin II with DAPI and Neurotrace (NT) as counterstains (D–G). (A) Right side of larval cerebellum shows location of Purkinje cell layer. Note large cell bodies and typical dendritic trees into molecular layer. (A’) Monochromatic picture visualizes Purkinje cell morphology. (B,C) This shows more caudal cerebellar levels including eminentia granularis. (B’) Enlargement of caudal Purkinje cells with one exhibiting an axon directed ventrally and exiting the cerebellum. (C’) Enlargement of terminal field in larval vestibular primary nuclear area formed by axon shown in (B’). Four transverse sections [levels indicated in drawing shown in (H)] from rostral (D) to caudal (G) show adult Purkinje cell bodies and dendrites in corpus cerebelli (D,E) and lobus caudalis cerebelli (F,F’), plus some Purkinje cells along the medial edge of eminentia granularis (arrowhead in E’). The cerebello-octavolateralis tract is highlighted by arrows in (E–E”,F) and forms a terminal field in the medial octavolateralis nucleus (E–E”) and in the descending octaval nucleus (G,G’). (D’) Enlargement of Purkinje cells giving rise to cerebello-octavolateralis tract (left brain side). See text for more details. Scale bars: 10 μm, that in (B) also applies to (C), in (D, also applies to E–G): 200 μm. CC, crista cerebellaris; CCe, corpus cerebelli; DV, descending trigeminal tract; CON, caudal octavolateralis nucleus; DON, descending octaval nucleus; EG, granular eminence; FLo, facial lobe; LCa, lobus caudalis cerebelli; LI, inferior lobe; LL, lateral line nerves; MO, medulla oblongata; MON, medial octavolateralis nucleus; MLF, medial longitudinal fascicle; OB, olfactory bulb; PG, preglomerular area; Pit, pituitary; RV, rhombencephalic ventricle; SC, spinal cord; SGT, secondary gustatory tract; Tel, telencephalon; TeO, optic tectum; TH, tuberal hypothalamus; TLa, torus lateralis; VLo, vagal lobe; I, olfactory nerve; II, optic nerve; IV, trochlear nerve; V, trigeminal nerve; VII, facial nerve; VIII, octaval nerve; X, vagal nerve.