Mark T A, Gallistel C R
Department of Psychology, University of California, Los Angeles 90024-1563.
Behav Neurosci. 1993 Apr;107(2):389-401. doi: 10.1037//0735-7044.107.2.389.
The growth of the subjective reward magnitude of medial forebrain bundle stimulation in the rat (Sprague-Dawley) as a function of train duration and pulse frequency was measured in 2 ways: (a) a titration method, which used differences in rate of reward on 2 levers to compensate for differences in the magnitude of the rewards; and (b) a direct method, in which the ratio of the reward magnitudes at the 2 levers was assumed to be given by the ratio of times spent on each lever. The results of the 2 methods agree. Reward magnitude grows as approximately a power function of train duration up to train durations of about 1 s, then declines somewhat over the interval from 2-20 s. The exponent of growth varies from 0.4 to 2.3. With stronger stimulation (higher pulse frequency), peak reward magnitude is bigger, but the saturating train duration is approximately the same.
采用两种方法测量了大鼠（斯普拉格-道利大鼠）内侧前脑束刺激主观奖励强度随串刺激持续时间和脉冲频率的变化：(a) 滴定法，该方法利用两个杠杆上奖励率的差异来补偿奖励强度的差异；(b) 直接法，该方法假定两个杠杆上奖励强度的比值由在每个杠杆上花费时间的比值给出。两种方法的结果一致。奖励强度在串刺激持续时间约为1秒之前近似呈幂函数增长，然后在2 - 20秒的区间内有所下降。增长指数在0.4到2.3之间变化。刺激越强（脉冲频率越高），峰值奖励强度越大，但饱和串刺激持续时间大致相同。
