Re-examination of the topographical localization of facial nucleus in the pig.

ABSTRACT

Previous publications have provided different descriptions of the topographical organization of the facial nucleus of the pig. Since swine is used in biomedical research due to its embryological, anatomical and physiological similarities to human, we have reinvestigated the anatomical organization of the facial nucleus with application of fluorescent retrograde tracer Fast Blue, antibody to choline acetyltransferase and acetylcholinesterase histochemistry. Our findings demonstrate that in the porcine medulla facial motoneurons constitute a large cellular group occupying the ventro-lateral medulla. The neuronal group is interposed rostro-caudally between the superior and inferior olive, and located ventro-medially to the spinal nucleus of the trigeminal nerve. The present results clarify the anatomical description of this important brain stem nucleus in the pig.