Hand T H, Franklin K B
Pharmacol Biochem Behav. 1983 May;18(5):695-9. doi: 10.1016/0091-3057(83)90008-4.
Rats were trained to bar-press for intermittent reinforcement on a concurrent schedule offering self-stimulation (SS) at the animal's choice of one of two different brain loci. On the concurrent schedule, the relative reward value of the two reinforcers is evaluated by the way the subject divides its session time responding for these reinforcers, thus yielding a rate-free measure of reward in addition to response rate data. In animals with electrodes in the lateral hypothalamus (LH) and prefrontal cortex (PFC), amphetamine dose-dependently increased response rates as well as the proportion of time allotted to LH stimulation, demonstrating that the reward value of LH stimulation was increased relative to PFC stimulation. This finding supports the hypothesis that DA systems modulate the rewarding value of LH but not PFC SS, and it suggests that differing neural mechanisms underlie these two behaviors. In animals with LH/ventral tegmental area (VTA) implants, amphetamine had no effect on preference, although it produced an overall increase in rate. This suggests that the drug elevates the rewarding value of LH and VTA stimulation to a similar degree, and that the two regions may have a common DA-related reward substrate. Finally, it was found that when the two reinforcers were equally preferred (50% session time allotted towards each reinforcer), response rates for the two rewards were not necessarily equal. This confirms that SS response rate is not a simple function of reward magnitude.
训练大鼠在并发程序下按压杠杆以获得间歇性强化，该程序允许动物在两个不同脑区中自主选择进行自我刺激（SS）。在并发程序中，两种强化物的相对奖励价值通过受试者分配给这些强化物的会话时间的方式来评估，因此除了反应率数据外，还产生了一种无速率的奖励测量方法。在电极植入下丘脑外侧（LH）和前额叶皮质（PFC）的动物中，苯丙胺剂量依赖性地增加了反应率以及分配给LH刺激的时间比例，表明LH刺激的奖励价值相对于PFC刺激有所增加。这一发现支持了多巴胺能系统调节LH而非PFC自我刺激的奖励价值这一假设，并表明这两种行为背后存在不同的神经机制。在植入LH/腹侧被盖区（VTA）的动物中，苯丙胺对偏好没有影响，尽管它使反应率总体上有所增加。这表明该药物将LH和VTA刺激的奖励价值提高到了相似的程度，并且这两个区域可能具有共同的与多巴胺相关的奖励基质。最后，发现当两种强化物同样受青睐时（每个强化物分配50%的会话时间），两种奖励的反应率不一定相等。这证实了自我刺激反应率不是奖励大小的简单函数。
