Liebman J M
Neurosci Biobehav Rev. 1983 Spring;7(1):45-72. doi: 10.1016/0149-7634(83)90007-6.
Despite numerous pharmacological investigations of intracranial self-stimulation (ICSS), the substrates of this behavior have yet to be completely understood. In view of the likelihood that inadequate methodology has hindered the quest for these substrates, the present review was undertaken. Criteria for ICSS methodology should include not only the ability to discriminate reward from gross performance deficit, but also adequate capacity (ability to generate experimental data at a reasonable rate). For numerous reasons, bar-pressing on a continuous reinforcement schedule fails the first criterion despite its ease and rapidity. The use of partial reinforcement schedules may alleviate some of these shortcomings. Analysis of drug-induced response decrement patterns can discriminate gross motoric incapacity from other variables, although the question of subtle response maintenance deficits remains to be answered. Measurements of response rates using alternative operants do not differentiate reward and performance adequately. More promising, "rate-free" measures using locomotion as an operant include the two-platform method of Valenstein and the "locus of rise" method. Comparison of drug effects on ICSS with those on alternate tasks are fraught with pitfalls including the problems of assuring equivalent rates and patterns of responding. The use of differential electrode placements is ideally suited for neurochemically well-characterized drugs, particularly if "double dissociations" can be established during studies of multiple placements. Presentation of different current intensities or frequencies permits the compilation of rate-intensity functions, and drug-induced shifts in these functions have considerable analytical power. Self-regulation of current intensity constitutes a powerful tool that has yet to realize its full potential in the pharmacological study of ICSS. Extensive studies involving self-regulation of stimulation duration ("shuttlebox" studies) suggest that this method may be highly versatile despite several practical difficulties. It is concluded that at least six of these methods appear to do a reasonable job of excluding gross performance deficit. However, the possible influences of other factors, such as subtle response maintenance deficit, incentive or arousal, remain to be resolved in view of the multifactorial nature of ICSS. Multiple tests for ICSS drug or lesion studies are advocated whenever feasible, as no single test appears capable of resolving all theoretical complexities.
尽管对颅内自我刺激（ICSS）进行了大量药理学研究，但这种行为的基础仍未完全明了。鉴于方法学上的不足可能阻碍了对这些基础的探索，因此进行了本综述。ICSS方法学的标准不仅应包括区分奖励与总体行为缺陷的能力，还应具备足够的能力（以合理的速率生成实验数据的能力）。由于多种原因，连续强化程序下的压杆操作尽管简便快捷，但却不符合第一个标准。使用部分强化程序可能会缓解其中一些缺点。药物诱导的反应递减模式分析可以区分总体运动能力丧失与其他变量，尽管细微的反应维持缺陷问题仍有待解答。使用替代操作来测量反应速率并不能充分区分奖励和行为表现。更有前景的是，以运动作为操作的“无速率”测量方法，包括瓦伦斯坦的双平台法和“上升轨迹”法。比较药物对ICSS和对替代任务的影响充满了陷阱，包括确保反应速率和模式等效的问题。使用不同的电极放置非常适合神经化学特征明确的药物，特别是如果在多个放置位置的研究中能够建立“双重解离”。呈现不同的电流强度或频率可以编制速率-强度函数，药物引起的这些函数变化具有相当大的分析能力。电流强度的自我调节构成了一种强大的工具，在ICSS的药理学研究中尚未充分发挥其潜力。涉及刺激持续时间自我调节的广泛研究（“穿梭箱”研究）表明，尽管存在一些实际困难，但这种方法可能具有高度的通用性。得出的结论是，这些方法中至少有六种似乎在排除总体行为缺陷方面做得相当不错。然而，鉴于ICSS的多因素性质，其他因素（如细微的反应维持缺陷、动机或唤醒）的可能影响仍有待解决。只要可行，就提倡对ICSS药物或损伤研究进行多项测试，因为没有单一测试似乎能够解决所有理论复杂性问题。
