Bouyer J J, Montaron M F, Buser P, Durand C, Rougeul A
Département de Neurophysiologie comparée, CNRS-UPMC, Paris, France.
Behav Brain Res. 1992 Oct 31;51(1):51-60. doi: 10.1016/s0166-4328(05)80311-0.
In this study performed on 10 cats we analysed the effects of limited lesions of nucleus medialis dorsalis of the thalamus (MD) on behaviour and on some specific electrocorticographic (ECoG) patterns, known from previous works to accompany various states of waking attentiveness. The animals were tested during 90 min in three distinct behavioural situations; a neutral one (NS) where they simply explored their environment and then usually went to sleep; a second one (FA) where they could watch a mouse (but not catch it), which favoured 'focussed' attentiveness accompanied by the development of rhythmic ECoG activities in the anterior frontoparietal cortex ('beta rhythms' at 40 Hz); a third one (EX) with a hidden mouse whose appearance the cat was waiting for ('expectancy') which rather than favouring the development of beta rhythms elicited the appearance of another rhythmic activity dominating in somatic area SI, 'mu rhythms' at 14 Hz. The duration of each waking behaviour and its ECoG concomitant as well as that of slow wave and of paradoxical sleep were compared in each cat before and after lesion. Our results showed that MD lesions situated in the posterior part of the nucleus tended to increase the time occupied by focussed attentive behaviour and the accompanying beta rhythms. On the other hand, anteriorly located MD lesions elicited a concomitant reduction of both manifestations, behavioural and electrocortical. No such contrasting effects could be systematically noticed for the durations of expectancy, of slow sleep and of paradoxical sleep. These findings were discussed considering previous data showing that at least two systems project upon MD, that play distinct--in a way even antagonistic--roles in focussed attention upon a target. Both originate from the ventral tegmental mesencephalic area; one reaches MD through the ventral striatum (nucleus accumbens), the other one through the amygdala. The MD nucleus thus receiving contrasting information may participate in a final adjustment of the attentive state of the animal to its environment.
在这项对10只猫进行的研究中，我们分析了丘脑背内侧核（MD）局限性损伤对行为以及某些特定脑电图（ECoG）模式的影响，这些模式在以往的研究中被认为与各种清醒注意力状态相关。在90分钟内，对动物进行了三种不同行为情境的测试：一种是中性情境（NS），它们只是简单地探索环境，然后通常会入睡；第二种是有食物奖励的情境（FA），它们可以观看一只老鼠（但不能抓住它），这种情境有利于“集中”注意力，并伴随着额顶叶前部皮质出现有节律的ECoG活动（40赫兹的“β节律”）；第三种是有隐藏老鼠的情境（EX），猫在等待老鼠出现（“期待”），这种情境并非有利于β节律的发展，而是引发了另一种在躯体感觉区SI占主导的有节律活动，即14赫兹的“μ节律”。在损伤前后，比较了每只猫每种清醒行为及其ECoG伴随情况的持续时间，以及慢波睡眠和异相睡眠的持续时间。我们的结果表明，位于核后部的MD损伤往往会增加集中注意力行为及其伴随的β节律所占据的时间。另一方面，位于前部的MD损伤会导致行为和皮层电活动这两种表现同时减少。对于期待、慢波睡眠和异相睡眠的持续时间，没有系统地观察到这种对比效应。结合先前的数据对这些发现进行了讨论，先前的数据表明至少有两个系统投射到MD，它们在对目标的集中注意力方面发挥着不同的——甚至在某种程度上是拮抗的——作用。两者都起源于腹侧被盖中脑区；一个通过腹侧纹状体（伏隔核）到达MD，另一个通过杏仁核到达MD。因此，接收对比信息的MD核可能参与了动物注意力状态对其环境的最终调整。
