The present study has been performed to investigate the neural axis of rat digastric muscle using viral tracer, pseudorabies virus. The upper nuclei to innervate digastric muscle were in accumbens nucleus, agran-ular insular cortex, central nucleus of amygaloid, lateral septal nucleus, frontal cortex, and subfornical organ etc, in telencephalon ; arcuate hypothalamic nucleus, lateral hypot-halamic area, medial preoptic nucleus, bed nucleus of stria terminalis, dorsomedial hypot-halamic nucleus, suprachiasmatic nucleus, paraventricular nucleus, and retrochiasmatic area etc, in diencephalon ; nucleus Darkschewitsch, interstitial nucleus of the medial logitudinal fasciculus, parabrachial nucleus, locus ceruleus, Kolliker-Fuse nucleus, trigeminal mesencephalic nucleus, red nucleus, substantia nigra, nucleus of posterior commissure, Edinger-Westphal nucleus, and dorsal raphe nucleus etc, in mesencephalon ; giganto-cellular reticular nucleus, raphe magnus nucleus, raphe pallidus nucleus, raphe obscuous nucleus, nucleus of solitary tracts, lateral reticular nucleus, parvocellular reticular nucleus, area postrema, facial nucleus, pontine reticular nucleus, pontine nucleus of trigeminal nerve and spinal nucleus of trigeminal nerve etc, in rhombencephalon. There are significant difference of numbers of PRV-Ba immunoreactive cells between right and left sides of brain in almost nuclei[P< 0.05]. But PRV-Ba immunoreactive cells were observed only ipsilaterally in accessory trigeminal motor nucleus, accessory facial nucleus and agranular insular cortex. Frontal cortex was the only area which were shown contralateral immunoreactivity. The results of this study provide anatomical support that both the cranial and caudal bellies are innervated by the same upper nuclei. The results also support the suggestion that the lower nuclei of digastric muscle, accessory trigeminal motor nucleus and accessory facial nucleus consist of somatotopic motor complex.