SUMMARYUsing a double labelling procedure by combining injections of the anterograde tracer Phaseoh vdguris leumagglutinin into different parts of the striatum with injections of the retrograde tracer choleratoxin subunit B into the parvicellular reticular formation of rats @cRF), it was found that the ventrolateral part of the striaturn (vlS) projects onto neurons in the dorsolatcral part of the substantia nigra pars reticulata (SNR), a region that, in turn, was found to project to the pcRF. In contrast, the dorsomedial part of the striatum (dmS) projects onto neurons in the ventrolateral part of the SNR, a region that was found not to project to the pcRF. These differential striato-nigro-reticular pathways are discussed in view of the differential role of the vlS and dmS in the expression of oral movements.