Vankov A, Hervé-Minvielle A, Sara S J
Institut des Neurosciences, CNRS URA 1488, Université Pierre et Marie Curie, Paris, France.
Eur J Neurosci. 1995 Jun 1;7(6):1180-7. doi: 10.1111/j.1460-9568.1995.tb01108.x.
Activity of single units of the noradrenergic nucleus locus coeruleus was recorded in rats during active exploration of a novel environment. Novelty was controlled by the placement of objects in given holes in a hole board. The basic protocol included a habituation session in which the holes were empty and an object session in which a novel object was placed in one of the two holes. During the habituation session, when the whole environment was unfamiliar, there was a phasic response the first time the rat visited any hole, which habituated after one visit. During the second session, when one of the holes contained an object, the cell fired when the rat encountered the novel object. There was no response to empty holes in this session. The neuronal response was markedly diminished or entirely absent on the second and subsequent visits to object-containing holes, indicative of rapid habituation. In some rats it was possible to run a second object session, when a new object was introduced into a previously empty hole. Visits to this hole elicited a robust response, which again habituated after one single visit. The results show that the responses of locus coeruleus to novelty or change, which has been demonstrated in formal learning situations, occurs in freely behaving rats while they are learning about a new environment. Moreover, the response to novelty and change in the environment is short-lived, rapidly habituating after one or two encounters with the stimulus.
在大鼠对新环境进行主动探索期间，记录了去甲肾上腺素能蓝斑核单个神经元的活动。通过在孔板的特定孔中放置物体来控制新奇性。基本实验方案包括一个习惯化阶段，此时孔是空的，以及一个物体阶段，此时在两个孔中的一个孔中放置一个新物体。在习惯化阶段，当整个环境都不熟悉时，大鼠第一次访问任何一个孔时会出现相位反应，在一次访问后就会习惯化。在第二个阶段，当其中一个孔中有一个物体时，当大鼠遇到新物体时细胞会放电。在这个阶段对空孔没有反应。在第二次及随后对有物体的孔的访问中，神经元反应明显减弱或完全消失，这表明快速习惯化。在一些大鼠中，可以进行第二个物体阶段，此时将一个新物体放入先前为空的孔中。对这个孔的访问引发了强烈的反应，在单次访问后同样会习惯化。结果表明，蓝斑核对新奇或变化的反应，这在正式学习情境中已得到证实，在自由活动的大鼠学习新环境时也会出现。此外，对环境中新奇和变化的反应是短暂的，在与刺激物接触一两次后会迅速习惯化。
