J. Anat. (1987), 155, pp. 195-202 195With 11 figures

Printed in Great Britain

A stereotaxic atlas of the medulla oblongata of the goat's brain

J. S. TINDAL, A. TURVEY AND L. A. BLAKE

Endocrinology and Animal Physiology Department, Animal and Grassland ResearchInstitute, Church Lane, Shinfield, Reading RG2 9AQ, U.K.

(Accept.-d 24 February 1987)

INTRODUCTION

In a previous publication (Tindal, Knaggs & Turvey, 1968), a stereotaxic atlas ofpart of the goat's brain was described, extending from the preoptic area in the forebrainto the level of the superior colliculus in the midbrain. The present paper describes themedulla oblongata of the goat's hindbrain in stereotaxic coordinates.

MATERIALS AND METHODS

Two 2 years old castrate, British Saanen male goats weighing 81 and 63 kg wereused. They were killed by intravenous infusion of pentobarbitone sodium B.P., thehead was severed from the body, perfused with 0 9% saline solution followed by 10%formalin (v/v) and mounted in a stereotaxic instrument (Libero Bonetti, Bologna,Italy) as described previously (Tindal et al. 1968). In brief, the vertical interaural planerepresents the zero reference point for anterior-posterior coordinates and the hori-zontal zero plane intersects the interaural point and a point 25 mm above the lowermargin of the orbit. Two vertical, stainless steel marker tubes (O.D. 0-55 mm) wereinserted into the brain through pre-drilled holes in the skull by means of stereotaxicelectrode carriers at coordinates posterior 10 mm, right lateral 3 mm and posterior20 mm, right lateral 3 mm. A horizontal marker tube (O.D 0-92 mm) was insertedrostrally into the brainstem at left lateral 2 mm and 5 mm below instrument heightzero (H-5). The brains were immersed in 10% formalin (v/v) for six days, after whichthey were dissected out of the skulls leaving the marker tubes in position. The tubeswere used to align each brain in turn on the stage of a sledge microtome which wasfrozen with solid carbon dioxide and ethanol. They were withdrawn as soon as thebrain was frozen securely in position. Serial 80 um sections were cut in the transversestereotaxic plane. Every 10th, 11th and 12th section was retained, thus providing a trioof sections every millimetre. One series of sections was stained with solochrome cyaninfor myelinated fibres (Page, 1965), one with toluidine blue for cells (Pearse, 1960) andone with luxol fast blue and cresyl violet for both cells and fibres (Kliiver & Barrera,1953). When the tracks left by the marker tubes in the stained sections were comparedin the two brains, they were found to agree within 0-5 mm for the positions of thevertical markers and agreed exactly for the positions of the horizontal markers. Thebrain of the 81 kg goat was chosen for the atlas. Sections were projected at x 10magnification in a photographic enlarger and drawings were made for planes P10-P20. Publications which were consulted for identification of brain structures werePapez (1929), Lim, Liu & Moffitt (1960) and Yoshikawa (1967). The terminology ofNomina Anatomica Veterinaria, 3rd ed. (1983) was followed.

J. S. TINDAL, A. TURVEY AND L. A. BLAKE

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Figs. 1-11. Tracings from projections of transverse sections of goat brain at 1 mm intervals fromposterior 10 mm (PlO) to posterior 20 mm (P20). Scales are in mm.

ABBREVIATIONS

Fibrae arcuatae internae;Fasciculus longitudinalis medialis;N. glossopharyngeus;N. hypoglossus;Nucleus cuneatus lateralis;Nucleus cuneatus medialis;Nuclei cochleares;Nucleus n. facialis;Nucleus n. hypoglossi;Nucleus tractus solitarius;Nucleus tractus spinalis n. trigemini;Nucleus parasympathicus n. vagi;Nucleus vestibularis caudalis;

NVL,NVM,0,

P,PC,R,RF,S,SA,T,TV,VI

Nucleus vestibularis lateralis;Nucleus vestibularis medialis;Nucleus olivaris;Tractus pyramidalis;Pedunculus cerebellaris caudalis;Raphe;Formatio reticularis;Tractus solitarius;Stria acoustica;Tractus spinalis n. trigemini;Tractus caudalis n. vestibularis;N. vagus.

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ARC,FLM,G,HY,NCL,NCM,NCO,NF,NHY,NS,NT,NV,NVC,

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RF pR

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Goat brain atlas 197

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J. S. TINDAL, A. TURVEY AND L. A. BLAKE

RESULTS

Transverse stereotaxic planes passing caudally at 1 mm intervals from posterior10 mm (P10) to posterior 20 mm (P20) appear in Figures 1-11.

DISCUSSION

The atlas extends from the obex at P20 as far rostrally as the junction of brainstemand cerebellum. Much guidance was obtained for the identification of structures fromPapez (1929). The atlases of the dog's brain by Lim et al. (1960) and of the goat's brainby Yoshikawa (1967) were also of great help, although the latter is without coord-inates. The interpretation of vestibulular nuclei, however, varies slightly between theseauthors. Thus, whereas Papez (1929) and Lim et al. (1960) consider the medial nucleusto be rostral to the inferior (caudal) nucleus, Yoshikawa (1967) shows it in a positionmedial to the caudal nucleus and in the present work the former interpretation hasbeen followed. In this context, the descending root of the vestibular nerve describedby Papez (1929), which is closely applied to nucleus vestibularis caudalis, has beentermed tractus caudalis n. vestibularis. One of the reasons for undertaking the presentatlas was to provide coordinates for the tractus solitarius and its associated vagalnuclei, and these are found in planes P15-P20. Finally, it should be noted that therecommendations of footnotes 396, 398 and 399 in Nomina Anatomica Veterinaria(1983) have been followed so as to use the terms nucleus parasympathicus n. vagi,nucleus cuneatus medialis, n. c. lateralis and nucleus olivaris in place of the formerterms nucleus dorsalis n. vagi, nucleus cuneatus, n. c. accessorius and nucleus olivarisinferior, respectively.

SUMMARY

A stereotaxic atlas has been prepared for the medulla oblongata of the adult goat'sbrain using the technique described previously (Tindal et al. 1968). The atlas consistsof transverse stereotaxic planes passing caudally at 1 mm intervals from posterior10 mm (P10) at the level of the junction between brainstem and cerebellum to posterior20 mm (P20) at the level of the obex.

The Animal and Grassland Research Institute is financed through the Agriculturaland Food Research Council.

REFERENCES

KLOVER, H. & BARRERA, E. (1953). A method for the combined staining of cells and fibers in the nervoussystem. Journal of Neuropathology and Experimental Neurology 12, 400-403.

LIM, R. K. S., Liu, C-N. & MorTirr, R. L. (1960). A Stereotaxic Atlas of the Dog's Brain. Springfield:Thomas.

Nomina Anatomica Veterinaria (1983), 3rd ed. Ithaca, New York: World Association of Veterinary Anat-omists.

PAGE, K. M. (1965). A stain for myelin using solochrome cyanin. Journal of Medical Laboratory Technology22, 224-225.

PAPEZ, J. W. (1929). Comparative Neurology. New York: Crowell.PEARSE, A. G. E. (1960). Histochemistry, 2nd ed. London: Churchill.TINDAL, J. S., KNAGGS, G. S. & TURVEY, A. (1968). The forebrain of the goat in stereotaxic coordinates. Journal

of Anatomy 103, 457-469.YOSHKAWA, T. (1967). Atlas of the Brains of Domestic Animals. Tokyo: University of Tokyo Press.

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