Stimulation of the first trigeminal branch using a 10 ms train of 5 pulses of 0.1 ms duration is performed on 17 healthy subjects (19-65 years of age) in order to assess the relationship between polysynaptic components of the blink reflex and perceptive and pain thresholds (ths). The mean value of tactile ths (Pth) is 2.22 +/- 0.86 mA; while R2, R3 and pain threshold values are 1.25 +/- 0.34, 3.52 +/- 1.94 and 4.78 +/- 2.77 times the Pth respectively. The pain ths average is 1.47 +/- 0.92 with regard to the R3 threshold. The R2 ths are very close to those of tactile perception, while those of R3 appear significantly related to the pain ths.