Jonasson Zachariah, Ballantyne John K, Baxter Mark G
Department of Psychology, Harvard University, Cambridge, Massachusetts 02138, USA.
Hippocampus. 2004;14(1):28-39. doi: 10.1002/hipo.10146.
A forced-choice discrimination paradigm was used in two experiments, to evaluate retrograde and anterograde amnesia in rats after hippocampal ablation. In a within-subjects design (Experiment 1), rats were trained on a set of 10 olfactory discriminations 4 weeks before surgery and on a separate set of 10 discriminations 1 week before surgery. In a mixed design (Experiment 2), rats were trained on olfactory discriminations in one of three conditions: condition 1 (10 discriminations at 4 weeks before surgery); condition 2 (10 discriminations at 1 week before surgery); or condition 3 (10 discriminations at 4 weeks before surgery and 10 discriminations at 1 week before surgery). Discriminations in both experiments were rapidly learned, requiring 7-10 trials to reach criterion. After training, half of the rats in each condition received bilateral neurotoxic lesions of the hippocampus, and the other half received sham surgery. One week after surgery, all rats were given a retention test, consisting of a single critical trial for each discrimination. In both experiments, rats with selective hippocampal lesions exhibited preserved retention of these olfactory discriminations with no observable retention gradient. A postoperative acquisition test for two new discriminations indicated that anterograde memory was also preserved, while a postoperative test of spatial learning in the Morris water maze confirmed that the hippocampal lesions impaired spatial learning. Together, these experiments refute the contention that the hippocampus is requisite for (non-spatial) olfactory memory consolidation, storage, or access, despite the condition that the information be rapidly acquired.
在两项实验中使用了强制选择辨别范式，以评估海马体切除术后大鼠的逆行性遗忘和顺行性遗忘。在一项被试内设计（实验1）中，大鼠在手术前4周接受一组10种嗅觉辨别的训练，并在手术前1周接受另一组10种辨别的训练。在一项混合设计（实验2）中，大鼠在以下三种条件之一接受嗅觉辨别训练：条件1（手术前4周进行10种辨别）；条件2（手术前1周进行10种辨别）；或条件3（手术前4周进行10种辨别，手术前1周进行10种辨别）。两项实验中的辨别学习都很快，需要7 - 10次试验才能达到标准。训练后，每种条件下的一半大鼠接受海马体的双侧神经毒性损伤，另一半接受假手术。手术后1周，所有大鼠都接受了一次保持测试，包括对每种辨别进行一次关键试验。在两项实验中，具有选择性海马体损伤的大鼠在这些嗅觉辨别上表现出保持完好，没有可观察到的保持梯度。对两种新辨别的术后习得测试表明顺行性记忆也得到了保留，而在莫里斯水迷宫中的术后空间学习测试证实海马体损伤损害了空间学习。总之，这些实验反驳了以下观点，即尽管信息是快速获取的，但海马体对于（非空间的）嗅觉记忆巩固、存储或提取是必需的。
