• LTD-like effect is enhanced by pairing quadripulse magnetic stimulation (QPS LTD) with peripheral electrical stimulation (PA LTD). • Interindividual variability is smaller in PA LTD -QPS LTD than in conventional QPS LTD. • PA LTD -QPS LTD can be useful for clinical applications in neurological disorders. Quadripulse magnetic stimulation (QPS) is useful for changing corticospinal excitability, but the long-term depression (LTD)-like effect considerably has low responder rate. To solve this problem, we modified inhibitory QPS (QPS LTD) by pairing it with the application of an electrical stimulus (ES) to peripheral nerves (paired-associative QPS [PA-QPS LTD ]), and investigated the effects of PA-QPS LTD on motor-evoked potentials (MEPs). The peripheral-nerve ES was applied at two timings with a synchrony to transcranial magnetic stimulation (TMS) over the primary motor cortex (M1). The intrapair interval between ES and TMS was the N20-peak latency plus 2 ms for PA LTP -QPS LTD , and N20-peak latency minus 5 ms for PA LTD -QPS LTD. MEPs elicited by TMS over the left M1 were recorded from the right abductor pollicis brevis muscle before and after the interventions. The responder rates of PA LTD -QPS LTD and QPS LTD was also studied. The PA LTD -QPS LTD induced larger LTD-like effect than QPS LTD , and the PA LTP -QPS LTD induced smaller aftereffect than QPS LTD. The responder rates were significantly higher for PA LTD -QPS LTD than for QPS LTD. The new protocol, PA LTD -QPS LTD , induces powerful and consistent LTD-like aftereffects in the corticospinal tract neurons. PA LTD -QPS LTD is suitable for use in physiological evaluations and therapeutic approaches in various neurological disorders. [ABSTRACT FROM AUTHOR]