Durantou F, Cazala P, Jaffard R
Laboratoire de Psychophysiologie, UA CNRS 339, Université de Bordeaux I, Talence, France.
Physiol Behav. 1989 Aug;46(2):253-8. doi: 10.1016/0031-9384(89)90264-3.
Spontaneous alternation behavior in a T-maze was studied in mice of the BALB/c strain implanted with a stimulation electrode in the lateral hypothalamus (LH). For animals receiving no electrical stimulation spontaneous alternation rates decreased as a function of the increasing time interval between the first and the second trial (intertrial interval ITI). Thus, as compared to chance rate alternation (41.4%), mice significantly alternated at the 30 sec ITI (73.2%), exhibited a slight but not significant tendency to alternate at 30 min (51.8%) and performed very close to chance at 6 hr (39.3%). Stimulation of the LH, using a low current intensity (5 microA) during the first arm-choice, modifies subsequent arm-choice tested on the second trial. The direction of the effect, however, is highly dependent on the ITI. Thus, as compared to nonstimulated animals, stimulated mice show a strong preference to return to the previously visited arm when the ITI was 30 min, while for an ITI of 6 hr they, in fact, significantly avoid that arm (alternation). These results indicate that LH stimulation induces facilitative effects on memory for events occurring on the 1st trial as clearly shown for the 6 hr ITI. In addition to its general facilitative effect, stimulation could induce a place-reward association of short-duration which could explain the fact that animals tend to return to the same arm at 30 min. Alternatively, it is suggested that stimulation might have short-lasting amnesiant properties. Both of these hypotheses are discussed.
在植入下丘脑外侧（LH）刺激电极的BALB/c品系小鼠中，研究了T迷宫中的自发交替行为。对于未接受电刺激的动物，自发交替率随着第一次和第二次试验之间时间间隔（试验间隔ITI）的增加而降低。因此，与随机交替率（41.4%）相比，小鼠在30秒ITI时显著交替（73.2%），在30分钟时表现出轻微但不显著的交替倾向（51.8%），在6小时时的表现非常接近随机水平（39.3%）。在第一次选择臂时使用低电流强度（5微安）刺激LH，会改变第二次试验中测试的后续臂选择。然而，效应的方向高度依赖于ITI。因此，与未刺激的动物相比，当ITI为30分钟时，受刺激的小鼠强烈倾向于返回先前访问过的臂，而当ITI为6小时时，它们实际上显著避开该臂（交替）。这些结果表明，LH刺激对第一次试验中发生的事件的记忆产生促进作用，6小时ITI的情况清楚地表明了这一点。除了其一般的促进作用外，刺激可能会诱导短期的位置奖励关联，这可以解释动物在30分钟时倾向于返回同一臂的事实。或者，有人认为刺激可能具有短期失忆特性。对这两种假设都进行了讨论。
