Walker S, Fouriezos G
School of Psychology, University of Ottawa, Ontario, Canada.
Behav Neurosci. 1995 Feb;109(1):168-79. doi: 10.1037//0735-7044.109.1.168.
Frequency thresholds for electrical self-stimulation of the medial forebrain bundle were estimated in rats while low frequencies of pulses were applied continuously. When continuous pulses were delivered to the same electrode that received the 0.5-s trains of response-initiated stimulation, thresholds decreased by the free-pulse frequency (Experiment 1), consistently across current (Experiment 2). Estimates of the reward added by concurrent, response-contingent stimulation of the opposite electrode of a bilateral pair predicted the drop in threshold caused by the noncontingent pulses applied to the opposite hemisphere (Experiment 3), again, robustly across test current (Experiment 4). Continuous pulses restricted to times between self-initiated trains lost their effect (Experiment 5). The perception of reward was invariant despite changes in the overall activity of the self-stimulation substrate.
在持续施加低频率脉冲的情况下，对大鼠内侧前脑束的电自我刺激的频率阈值进行了估计。当将连续脉冲施加到接受0.5秒反应引发刺激序列的同一电极时，阈值会以自由脉冲频率降低（实验1），在不同电流下均一致（实验2）。对双侧电极对中对侧电极进行并发、反应性刺激所增加的奖励估计，预测了施加到对侧半球的非条件脉冲所导致的阈值下降（实验3），同样，在不同测试电流下都很显著（实验4）。仅限于自我引发序列之间时间的连续脉冲失去了其效果（实验5）。尽管自我刺激基质的整体活动发生了变化，但奖励感知是不变的。
