The nucleus of the tractus solitarius of the dog. A morphological and morphometric analysis.

The neuronal and fibrous architecture of the nucleus of the tractus solitarius (NTS) of the dog has been studied in transversely cut Nissl, myelin and reduced silver stained serial sections. Eight distinct subdivisions, clearly delimited both by their cytoarchitectonic and fibrous characteristics, have been identified. They are: the commissural, gelatinous, lateral, interstitial, dorsolateral, ventrolateral, intermediate and medial subdivisions. Their rostrocaudal extensions and locations in relation to the obex are summarised in Table 1. A morphometric analysis was additionally done. The frequency distributions of cell areas and cell form factor of each subdivision are represented by histograms in Figures 8 and 9 respectively.