Wheeling H S, Kornetsky C
Brain Res. 1983 Aug 1;272(1):13-9. doi: 10.1016/0006-8993(83)90359-1.
Current intensity thresholds for the detection of electrical brain stimulation were determined from a variety of forebrain and midbrain sites in rats. In a discrete trial, instrumental paradigm, the detection stimulus delivered via one electrode acted as a cue for the availability of response contingent rewarding brain stimulation delivered via a second electrode in the posterolateral hypothalamus. The current intensity of the detection stimulus (20 Hz) was varied according to a modification of the psychophysical method of constant stimuli, while the intensity of contingent rewarding stimulation (160 Hz) was fixed at a highly reinforcing level. Detection thresholds measured from forebrain sites were significantly lower than thresholds from midbrain sites. This difference in detection thresholds was not related to any variability between subjects in site or parameters of the rewarding stimulus used to maintain behavior. Lower detection thresholds from forebrain loci may be due to greater sensitivity to electrical stimuli at the detection site or of the pathways from those sites to areas mediating perception or conditioning.
通过对大鼠前脑和中脑的多个部位进行研究，确定了检测脑电刺激的当前强度阈值。在一个离散试验的工具性范式中，通过一个电极施加的检测刺激作为一种提示，表明通过后外侧下丘脑的第二个电极提供的与反应相关的奖励性脑刺激是可用的。检测刺激（20赫兹）的电流强度根据对恒定刺激心理物理学方法的改进而变化，而奖励性刺激（160赫兹）的强度则固定在一个高度强化的水平。从前脑部位测得的检测阈值明显低于从中脑部位测得的阈值。检测阈值的这种差异与维持行为所使用的奖励刺激的部位或参数在不同受试者之间的任何变异性无关。前脑位点较低的检测阈值可能是由于检测部位对电刺激或从这些部位到介导感知或条件作用区域的通路具有更高的敏感性。
