Fig. 1

Brain schematics in lateral view for amniotes (a, d), teleosts (b, e) and amphibians (c, f) point out neuromeric divisions. Left side panels [a–c; adapted from Wullimann, 2020] emphasize forebrain with pretectal (P1) prosomere in dark gray, (dorsal) thalamic (P2) prosomere in green and ventral thalamic/prethalamic (P3) in blue. Note that for reasons given in the text, an early version of the amniote prosomeric model [Puelles and Rubenstein, 1993] is given in (a, d). In contrast, the zebrafish model follows in general that proposed by Wullimann and Puelles [1999]. Positions of early migrated teleostean forebrain areas M1 through M4 are highlighted (orange structures in B). In midbrain and hindbrain (a–c), primary neuromeric locations of motor nuclei (red) are shown [after Gilland and Baker, 2005, zebrafish efferent octavolateralis and facial motor neurons after Beiriger et al., 2021]. Right side panels [d–f; adapted from Vernier and Wullimann, 2009] emphasize basal plate portions of prosomeres (bPs in dark gray) and dopamine systems in midbrain and forebrain (pink structures) interpreted within the neuromeric model. Mouse A8-A15 dopamine cell groups correspond to the nomenclature of Smeets and González [2000] and Björklund and Dunnett [2007]. The Arabic numbers of zebrafish dopamine cell groups are taken from Rink and Wullimann [2002]. Xenopus dopamine nuclei are according to González et al. [1994a, b], González and Smeets [1994], Smeets and González [2000], and Xavier et al. [2017]. The inset in (d) shows Ngn2 expression in the mouse diencephalon at this sagittal section level (modified from Osório et al. [2010]; see text). In the hindbrain (d, e) secondary (tangentially migrated) positions of various motor nuclei (red-rimmed) are shown [after Gilland and Baker, 2005; zebrafish efferent octavolateralis and facial motor neurons after Beiriger et al., 2021]. Prosomeric and rhombomeric boundaries are indicated by dashed lines. g Postembryonic zebrafish brain proliferation zones visualized either with PCNA [Wullimann and Puelles, 1999; Wullimann and Knipp, 2000] or BrdU [Mueller and Wullimann, 2002a] support prosomeric model [Puelles and Rubenstein, 1993]. Modified from Mueller and Wullimann [2016]. Alar plate (dorsal) and basal plate (ventral) are separated by a chain line along the anteroposterior axes (note flexures deviating from general body axis; see text). h Schema shows larval brain zebrafish brain schema in lateral view with indication of general body axes on top and in red the anteroposterior and dorsoventral (alar-basal) neuraxes that respect the brain curvature [modified from Herget et al., 2014]. Additionally, intrahypothalamic neuraxes are indicated, and tuberal (gray) and mammillary (light blue) basal hypothalamic parts are highlighted (see text for details). i Larval zebra­fish basal hypothalamus with various landmark-providing markers [after Wang et al. [2001]; Rink and Guo [2004]; Forlano and Cone [2007], general basal hypothalamic gene expression (see text for citations) and specific tuberal (TubH) and mammillary hypothalamic (MamH) gene expression after Schredelseker and Driever [2020]. a, anterior; ac, anterior commissure; AEP, anterior entopeduncular area (mouse); Agrp, Agouti-related protein; AH, anterior hypothalamus (mouse); bP1-3, basal parts of prosomeres 1–3; Ce, cerebellum; CeP, cerebellar plate; Crhbp, corticotropin-releasing hormone binding protein; d(a), dorsal(alar); Dop, dopamine; DT, dorsal thalamus; E, epiphysis; EGL, external granular layer; EmT, eminentia thalami; H, hypothalamus; Ha, habenula; Hc, Hi, Hr, caudal, intermediate, rostral periventricular hypothalamic zone; HC, hypothalamic cell cord (mouse); Hist, histamine; InCo, inferior colliculus; M1, early migrated pretectal aera; M2, early migrated posterior tubercular area (preglomerular complex); M3, early migrated area of eminentia thalami; M4, early migrated telencephalic area; MA, mammillary hypothalamus (mouse); MamH, mammillary hypothalamus (zebrafish); md, mediodorsal tectal proliferation; MO, medulla oblongata; MSH, α-melanocyte-stimulating hormone; mv, medioventral tectal proliferation; N, area of the nucleus of the medial longitudinal fascicle; OB, olfactory bulb; oc, optic chiasm; p, posterior; P, pallium; P1-P3, prosomeres 1–3; PEP, posterior entopeduncular area (mouse); Po, preoptic region; POA, anterior preoptic area (mouse); poc, postoptic commissure; POP, posterior preoptic area (mouse); Pr, pretectum; PTd, dorsal posterior tuberculum; PTv, ventral posterior tuberculum; PTM, posterior tectal membrane; RCH, retrochiasmatic hypothalamus (mouse); RCT, rostral cerebellar thickening (valvula); Rho-AP, alar plate proliferation of rhombencephalon; Rho-BP, basal plate proliferation of rhombencephalon; RL, rhombic lip; S, subpallium; SC, spinal cord; Sd, dorsal division of subpallium; SePr, secondary prosencephalon; SH, suprachiasmatic area (mouse); SPV, supraopto-paraventricular area; SuCo, superior colliculus; Sv, ventral division of subpallium; T, midbrain tegmentum; TeO, tectum opticum; TeVe, tectal ventricle; TS, torus semicircularis; TU, tuberal hypothalamus (mouse); TubH, tuberal hypothalamus (zebrafish); v(b), ventral(basal); Va, valvula cerebelli; VCP, ventral cerebellar proliferative layer; Ve, forebrain ventricle; VT, ventral thalamus (prethalamus); VTA/SN, ventral tegmental area/substantia nigra, x location of ventricular proliferation zone of EmT; ZLI, zona limitans intrathalamica. 1–8 rhombomeres 1 through 8, additionally in panel e: 1–7 designate larval zebrafish dopaminergic cells groups (see text for details), III, IV,V (Va/Vp), VI (VIa/VIp), VII, VIII, IX, X, XII ocolumotor, trochlear, trigeminal (anterior/posterior trigeminal), abducens (anterior/posterior abducens), facial, octavolateralis efferent, glossopharyngeal, vagal, hypoglossal motor nuclei, 5-HT 5-hydroxytryptamine.