The cervicothalamic tract terminates in Cat301-sparse regions of the cat VPL

The termination pattern of the cervicothalamic tract (CTI), labelled with anterogradely transported WGA-HRP, was compared with the immunolabelling pattern obtained with the monoclonal antibody Cat301 in adjacent sections through the ventral posterolateral nucleus (VPL). CTT terminations are located in peripheral parts of the medial and lateral parts of the VPL (VPLm and VPL1), being more extensive in the caudal than in the rostral parts of the subnuclei, and in the dorsal part of VPL1 and dorsolateral part of VPLm, regions that are all sparse in CAt301 immunoreactivity. Central regions of the VPL with dense Cat301 immunolabelling contain only very sparse CTT termination. Thus, our findings show that the CTT innervates a compartment of the VPL that is characterized by sparse Cat301 immunoreactivity.