Manning A A, Vierck C J
J Exp Anal Behav. 1973 Jan;19(1):125-32. doi: 10.1901/jeab.1973.19-125.
Cebus albifrons monkeys received electrical stimulation of the hindlimbs over a wide range of intensities. On trials signalled by a blue light, the animals were permitted to escape shock by pressing a disc, or shock was terminated after 8 sec (free escape). Escape force (disc pressure) was found to increase as stimulation intensity increased well beyond escape threshold, while shock duration curves reached plateau at the mid-range of intensities. The shock duration curves generated by free escape responses should be comparable to pain detection functions obtained by similar operations in humans, and the curves were stable over months of testing, as is generally found in pain-detection studies. On trials signalled by a red light, the animals received intense tail shock immediately after escape responses (punished escape), or, if they endured leg shock for 8 sec without escaping, then they could avoid tail shock with a panel press. The shock duration curves generated by punished escape responses should be comparable to pain tolerance functions as defined for human subjects, and the escape thresholds were considerably higher on red-light trials. As in human studies, the tolerance curves were not stable over repeated testing sessions, and some feature of the paradigm forced a progression toward extremely high levels of tolerance.
白额卷尾猴接受了在很宽强度范围内的后肢电刺激。在由蓝光信号指示的试验中，动物被允许通过按压圆盘来逃避电击，或者在8秒后电击终止（自由逃避）。发现逃避力（圆盘压力）随着刺激强度增加而增加，远远超过逃避阈值，而电击持续时间曲线在强度的中间范围达到平稳状态。由自由逃避反应产生的电击持续时间曲线应该与通过在人类中进行类似操作获得的疼痛检测功能相当，并且这些曲线在数月的测试中是稳定的，这在疼痛检测研究中通常会发现。在由红光信号指示的试验中，动物在逃避反应后立即接受强烈的尾部电击（惩罚性逃避），或者，如果它们忍受腿部电击8秒而不逃避，那么它们可以通过按压面板来避免尾部电击。由惩罚性逃避反应产生的电击持续时间曲线应该与为人类受试者定义的疼痛耐受功能相当，并且在红光试验中逃避阈值要高得多。与人类研究一样，耐受曲线在重复测试过程中不稳定，并且该范式的某些特征迫使耐受性朝着极高水平发展。
