The nucleus of BELLONCI in birds - DWC

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1096 t r. thdl,front. med 1/ intenn pala,:ostr.d tr. str.-teqm .,, ~.:.:.....;.~~ +quint:fr. h: sept:mesenc. .. . rarn.dors. -0. ' .:......'-'-~ nuel. Bellonci h. opt. nud. ~en . lat. ventr. I. 11 dors. nud. pos~v td.ect-th . ~ th~tect. "ud. rot. nucU.r. hab'-ped. ud. spirif. r·me". i5thrn~opt. f.mes.l.d.c. nuc.\. mes. lat. p.v. nuc/. isthmi prine. pal·voc. h ... tec.t7 spirit. med. nllef. spi rif. r./at . Fig. 3. SPARROW. Sagittal section through middle (in transverse direction) of nucleus of BELLONCI. WEIGE/?T-PAL-paracarmine. X 10. III1t1Jasc.diaf Broe" dec.. supra ort. dors. tr. septolnes. MIJl.d. t r. str~tes'IT1.~cer. +quint,fr. +sept,mes.r.b.c. t,.. tha/, Fr. inier .. !r. nlld. ovoid tI'. sept7mesenc. tr.fr"arch. I! ne o:,tr. uel. pas. palaeostr. augm . tr. fr,arch. 6neostr. p.metl. + co rt7hi\b./öt.dnt:. nuc.1. Bellon,i h . 0Ft. marS'. gris. ted. teet.opt. '-";,~.:..,..:,,~_ hur!. spirif lat. ·:';::';T~+~~nud . mes . \.d.s . .. " c, nuc.l.poshl ong.med. tr.tC~ct,' bUIID:d IJ I' Fig. 4. SPARROW. Horizontal section through middle (in vertical direction) of nucleus of BELLONCI. WEIGERT- PAL-alum-carmine. X 10. EXPLANATION OF SOME OF THE ABBREVIATIONS US ED IN THE FIGURES . a, differentiated portion of hyperstriatum accessorium (see HUBER and CROSBY, 1929) . comp. sept.-mes. stro m., component from tractus septo-mesencephalicus to stria medullaris. gris. tect., griseum tecti, tectal gray of HUBER and CROSBY (1929) . nucl. ace. post., nucleus accumbens pars posterior. nucl. bas., nucleus basalis. nucl. intere. lam. sup., nucleus intercalatus laminae supenons (see KAPPERS, HUBER and CROSBY, 1936). nucl. intere. lam. supr., nucleus intercalatus laminae supremae (see KAPPERS, HUBER and CROSBY, 1936).
1097 nucl. mes. I. d. c., nucleus mesencephalicus nucl. post.-interm., nucleus posterolateralis pars dorsalis centralis. intermedius. nucl. mes. I. d. s., nucleus mesencephalicus nucl. post.-ventr., nucleus postero-ventralis. lateralis pars dorsalis superficialis. nucl. sept.-hipp., nucleus septo-hippocamnucl. periv. m. acc., nucleus periventricularis palis. magnocellularis accessorius (see KUROT- tr. gen.-front. ventr., tractus geniculosu, 1935). frontalis ventralis (see FREY, 1937). nucl. periv. m. pr., nucleus periventricularis tr. sept.-mes. r. b. C., tractus septo-mesenmagnocellularis principalis (see KUROT- cephalicus ramus basalis caudalis. su, 1935). by a ma ss of loosely arranged fine myelinated fibres th at seem to come Erom the dorsal supraoptic decussation (figs. I , 2). These fibres diverge in the direction of the nucleus, embrace and traverse it, but at its lateral side again collect. Farther they could not be followed with certainty in the sparrow. In the dove, wh ere they are much bet ter studied, we shall revert to them. Also in this bird the nucleus of BELLONCI is an ellipsoid (figs. 5, 6) , but here the major axis, in contradistinction with the sparrow, where it lies in a transverse plane, is directed sagittally, while the longer of the minor axes, which IS but little shorter than the major axis, extends almost vertically. In the dove the nucleus of BELLONCI shows about the same relationships to the neighbouring nuclei as in the sparrow, but those to the neighbouring and possibly synapsing tracts are somewhat different, in that the ramus dorsalis of the tractus septo-mesencephalicus is only in contact with the oral extremity of the nucleus. Very soon this tract, leaving the nucleus, turns dorsomedially, and runs caudalward along the surface of the brain (figs. 5, 6) . No more than in the sparrow the origin of the fibres coming from ventromedial could be ascertained in the dove, though they are far more numerous here. All that I can say is that they seem to come from the dorsal supraoptic decussation. Part of them swing medially across the dorsal peduncle of the lateral forebrain bundIe and join the stria medullaris, another part do so with the ramus dorsalis of the tractus septo-mesencephalicus. The latter, however, is connected by a compact strand of fibres, coursing along the surface of the brain, with the stria medullaris (fig. 6) . These connecting fibres, in part at least, may be the same as that portion of the fibres coming from ventromedial which joined the tractus septomesencephalicus. Evidently the loose fibre mass coming from ventromedial represents the tractus olfacto-habenularis lateralis, which originates in the preoptic and hypothalamic regions. This fibre ma ss has not been seen by HUBER and CROSBY (1929) , who state that they could not identify a tractus olfactohabenularis lateralis in birds. The strand of fibres, however, connecting the septo-mesencephalic tract with the stria medullaris, has been observed Proc. Ned. Akad. v. Wetenseh., Amsterdam, Vol. XLIII, 1940. 71
Page 1 and 2: Anatomy. - The nucleus of BELLONCI
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Page 7 and 8: 1099 by H UBER and CROSBY (their co
Page 9 and 10: 1101 that its chief supply is by fi
Page 11 and 12: 1103 lateralis anterior relative to
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The nucleus of BELLONCI in birds - DWC

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