threshold stimulus; liminal stimulus
Technical term in physiology and psychology for the weakest stimulus that can just be detected or produce a response.
At intensities below the threshold stimulus, no sensation occurs.
In this experiment, we gave the subjects a threshold stimulus and measured their reaction time.
刺激 is a general stimulus; 閾刺激 specifically refers to the minimal detectable stimulus.
Compound of 閾 (threshold) and 刺激 (stimulus). The exact historical derivation is uncertain, but the term is a modern technical coinage.