Blackburn J R, Hevenor S J
Department of Psychology, McMaster University, Hamilton, Ont. Canada.
Behav Brain Res. 1996 Oct;80(1-2):41-9. doi: 10.1016/0166-4328(96)00017-4.
Three experiments investigated the effects of d-amphetamine on the performance of rats on tasks that required the discrimination of configural cues (i.e., those in which two stimulus elements, tone and light, have a meaning when presented together that is distinct from the meaning of the same elements presented in isolation from each other). In a negative patterning task (Experiment 1), rats were trained in a GO/NO-GO task in which either stimulus alone signalled reward availability whilst the compound did not. Amphetamine (0.5, 1.0 and 2.0 mg/kg) was found to disrupt performance by increasing responses to the unrewarded compound. Responses were also increased during the ITI. In contrast, in Experiments 2 and 3 amphetamine had little impact on performance on a task in which the rats had to respond to either of the single stimuli with one response (lever-press or chain-pull) and to the compound stimulus with the other response. The results add credence to the suggestion of Davidson et al. (Behav. Neurosci., 1993, 107, 227-234) that hippocampal lesions disrupt negative patterning by increasing responsiveness rather than by disrupting a configural association system and do not support the idea that increased dopamine activity disrupts configural associations. The findings are discussed in the context of hippocampal-dopamine interactions.
三项实验研究了右旋苯丙胺对大鼠在需要辨别构型线索任务中的表现的影响（即，在这些任务中，两种刺激元素，音调与光，当一起呈现时具有一种与它们单独呈现时不同的意义）。在一项负性模式任务（实验1）中，大鼠在一个“是/否”任务中接受训练，其中单独的任何一种刺激都表明有奖励可得，而复合刺激则不然。结果发现，苯丙胺（0.5、1.0和2.0毫克/千克）通过增加对无奖励复合刺激的反应而干扰了任务表现。在间隔时间内反应也增加了。相比之下，在实验2和3中，苯丙胺对大鼠在一项任务中的表现影响很小，在该任务中，大鼠必须用一种反应（按压杠杆或拉链条）对单一刺激之一做出反应，并用另一种反应对复合刺激做出反应。这些结果为戴维森等人（《行为神经科学》，1993年，第107卷，第227 - 234页）的观点提供了支持，即海马损伤通过增加反应性而不是通过破坏构型关联系统来干扰负性模式，并且不支持多巴胺活性增加会破坏构型关联的观点。这些发现将在海马 - 多巴胺相互作用的背景下进行讨论。
