Thornton E W, Davies C
Department of Psychology, University of Liverpool, England.
Physiol Behav. 1991 Apr;49(4):819-22. doi: 10.1016/0031-9384(91)90324-h.
Although the habenula occupies a potentially important link between forebrain and midbrain, lesion of the complex produces little effect in most standard behavioral paradigms. More recently, it has been shown that such lesions may impair the ability to initiate or switch responses appropriate to environmental contingencies but only under demanding conditions. Although such deficits have been described as response failures, they could equally well be attributed to restricted attentional mechanisms. The present study was designed to further substantiate a role for the habenula in acquisition of adaptive behavior under demanding conditions and to examine the possible contribution of attentional failure. The initial response preference to 'escape' onto platforms situated in two chambers at the distal end of a water tank was established for groups of lesioned and sham-operated rats. Rats were subsequently trained in discrete trials to escape by choosing the side of the nonpreferred chamber. During training the choice of escape chamber was cued by distracting black or white visual stimuli displayed on the tank sides and above the entrances to the chamber. These were moved over trials so as to be nonpredictive of the appropriate escape position. Lesioned animals were significantly impaired in the acquisition of this positional discrimination. Analysis of response times suggested that both lesion and control animals were attending to the irrelevant visual cue. The results confirm a behavioral inflexibility following lesion of the habenula and suggest that this deficit cannot be explained simply in terms of a failure to attend to environmental cues. The lesion deficit also could not be attributed to a response perseveration.
尽管缰核在前脑和中脑之间占据着潜在的重要联系，但在大多数标准行为范式中，该复合体的损伤产生的影响很小。最近有研究表明，此类损伤可能会损害启动或切换适合环境突发事件的反应的能力，但仅在苛刻条件下才会如此。尽管此类缺陷被描述为反应失败，但它们同样也可归因于受限的注意力机制。本研究旨在进一步证实缰核在苛刻条件下适应性行为习得中的作用，并探讨注意力失败可能产生的影响。为损伤组和假手术组大鼠建立了最初对“逃到”位于水箱远端两个隔室中的平台上的反应偏好。随后，大鼠在离散试验中接受训练，通过选择非偏好隔室的一侧来逃生。在训练过程中，通过在水箱两侧和隔室入口上方显示的分散注意力的黑色或白色视觉刺激来提示逃生隔室的选择。这些刺激在试验过程中移动，从而无法预测合适的逃生位置。损伤动物在这种位置辨别学习中明显受损。反应时间分析表明，损伤组和对照组动物都在关注无关的视觉线索。结果证实了缰核损伤后行为的灵活性受损，并表明这种缺陷不能简单地用未能关注环境线索来解释。损伤缺陷也不能归因于反应固执。
