Martin L T, Alberts J R
J Comp Physiol Psychol. 1982 Aug;96(4):668-75. doi: 10.1037/h0077901.
Infant rat pups (3-4 days of age) that received a single pairing of a novel odor (CS) with illness later responded to the CS with sustained accelerations in heart rate (HR); a different novel odor evoked deceleratory HR responses. Control pups responded to the CS and the second novel odor with cardiac deceleration. In a second experiment, rat pups that received three pairings of a novel odor with a cold (10 degrees C) temperature reinforcement displayed a similar pattern of HR responses, i.e., acceleration to the CS and deceleration to the novel odor. Cardiac response patterns are a useful measure of learning in infant mammals. The directional modulations of HR found in these experiments compare favorably with previous interpretations of "orienting" and "defensive" reactions derived from studies of HR responses in humans.
3至4日龄的幼鼠在将一种新气味（条件刺激）与疾病进行单次配对后，之后对该条件刺激会出现心率（HR）持续加快的反应；另一种不同的新气味则会引起心率减慢反应。对照幼鼠对条件刺激和第二种新气味的反应是心率减慢。在第二个实验中，幼鼠在将一种新气味与寒冷（10摄氏度）温度强化进行三次配对后，表现出类似的心率反应模式，即对条件刺激心率加快，对新气味心率减慢。心脏反应模式是衡量幼龄哺乳动物学习情况的有用指标。在这些实验中发现的心率定向调节与先前从人类心率反应研究中得出的“定向”和“防御”反应的解释相当吻合。
