[Localization of neurons innervating vibrissae in the mouse in the Gasserian ganglion: retrograde peroxidase transport study and morphometric analysis].

Two methods were used in an attempt to localize within the trigeminal ganglion the neurons whose axons innervate mouse mystacial vibrissae. First, the loss in the bulk area occupied by neuronal cell bodies in the ophthalmo-maxillary part of the ganglion in two-month old mice, whose vibrissae follicles were coagulated unilaterally at birth, was evaluated morphometrically in four sectors of each section. Secondly, neurons labelled by the injection of peroxidase in the vibrissae follicles of adult mice were localized in the ganglion. The results indicate that the neurons which ensure the sensitive innervation of the vibrissae are situated in the median area of the ophthalmo-maxillary part of the ganglion, extending more rostrally than caudally, mainly in ventral position. A certain degree of somatotopy is demonstrated by the comparative study of neurons labelled by the injection of peroxidase in the anterior or posterior follicles. The neurons which correspond to the anterior vibrissae are mainly ventral, while they are both dorsal and ventral for the posterior vibrissae.