In the context of impulsive decision-making, delay discounting is a phenomenon observed when participants refer to the preference for a smaller reward sooner rather than a larger reward later in reward receipt. Previous neuroimaging findings showed that the dorsolateral prefrontal cortex (DLPFC) contributes to predicting the selection of larger-later over smaller-sooner rewards. However, recent studies on delay discounting offer mixed conclusions. This study aimed to examine how impulsive decision-making affects the signal transfer from the left DLPFC to the primary motor cortex (M1) by using dual-site paired-pulse transcranial magnetic stimulation (ppTMS) (n=6). In this protocol, the interval of ppTMS in DLPFC-M1 interaction measurements was set at 10 and 50 ms. The conditioning coil was applied on the left DLPFC with the intensity of 110% rest motor threshold (RMT), while the test coil was applied on M1 with 130%RMT. Motor-evoked potentials (MEPs) induced by ppTMS and single-pulse TMS (spTMS) were compared before or after a 27-item monetary choice task. Our results showed that MEPs induced by DLPFC-M1 interaction at 50 ms were inhibited after the delay discounting task (t5 = 2.820, p = 0.037) but not in 10 ms interaction or spTMS measurements. This result demonstrates that the left DLPFC was involved in the impulsive decision-making process and the DLPFC-M1 interactions were inhibited by the delay discounting task, indicating the left DLPFC may have an inhibitory projection to the motor area during the task. Our findings may have implications for the treatment of specific disorders like at-risk adolescents or substance addiction.