Markou A, Koob G F
Department of Neuropharmacology, Scripps Research Institute, La Jolla, CA 92037.
Physiol Behav. 1992 Jan;51(1):111-9. doi: 10.1016/0031-9384(92)90211-j.
A discrete-trial current-threshold intracranial self-stimulation (ICSS) paradigm has been used extensively to examine the effects of drugs on reward thresholds. However, there is little work to date validating that this specific procedure measures reward. The purpose of the present study was to establish the construct validity of this procedure by testing the procedure's ability to measure reward effects and to discriminate these reward effects from performance effects. The discrete-trial ICSS procedure provides four measures: current thresholds, response latency, extra responses and time-out responses. The effects of a performance manipulation (variations in the force required to operate the manipulandum) and of a reward manipulation (variations in the train duration of the electrical stimulation) were evaluated on the four measures. Reward effects were reflected primarily in changes in thresholds, with no effect on any of the other three measures. Conversely, performance effects were reflected primarily in changes in response latency, extra responses and time-out responses, with only a small effect on thresholds. Finally, the paradigm's potential as a useful tool in the elucidation of the neurobiological basis of reward was demonstrated by investigating the effects of two pharmacological agents, cocaine and curare, on the four measures derived from the discrete-trial current-threshold ICSS procedure. The results suggest that the discrete-trial current-threshold procedure can readily discriminate reward from performance treatments.
一种离散试验电流阈值颅内自我刺激（ICSS）范式已被广泛用于研究药物对奖赏阈值的影响。然而，迄今为止几乎没有研究验证这一特定程序是否能测量奖赏。本研究的目的是通过测试该程序测量奖赏效应以及区分这些奖赏效应与行为表现效应的能力，来确立该程序的结构效度。离散试验ICSS程序提供了四项测量指标：电流阈值、反应潜伏期、额外反应和超时反应。评估了行为表现操作（操作手柄所需力量的变化）和奖赏操作（电刺激的串时程变化）对这四项测量指标的影响。奖赏效应主要反映在阈值变化上，对其他三项测量指标均无影响。相反，行为表现效应主要反映在反应潜伏期、额外反应和超时反应的变化上，对阈值仅有微小影响。最后，通过研究两种药物可卡因和箭毒对离散试验电流阈值ICSS程序得出的四项测量指标的影响，证明了该范式作为阐明奖赏神经生物学基础的有用工具的潜力。结果表明，离散试验电流阈值程序能够轻易地区分奖赏处理和行为表现处理。
