Numan R, Feloney M P, Pham K H, Tieber L M
Department of Psychology, Santa Clara University, CA 95053, USA.
Physiol Behav. 1995 Dec;58(6):1263-71. doi: 10.1016/0031-9384(95)02044-6.
Previous work in our laboratory has found that whereas medial septal lesions impaired an operant left-right delayed alternation task in rats, the lesion also facilitated the performance of rats on a cued go/no-go discrimination task with a delay between the cue and the required response. These findings suggested to us that the medial septal lesions impaired "response" working memory, which in turn led to a compensatory enhancement of attention to stimulus cues. If this hypothesis is true, then the lesions should impair a go/no-go task based on "response" working memory. The current experiment tested this hypothesis. Rats (12 with medial septal lesions and 12 with sham operations) were tested on a discrete trial operant go/no-go response alternation task. The rats were first tested for 20 days without a delay contingency, followed by 35 days of testing with a 15-s delay between "go" and "no-go" trials. Both groups became proficient at the task under nondelay conditions and their terminal performance (averaging about 85% correct) did not differ. However, under delay conditions the performance of the lesioned rats was significantly impaired compared to the controls. As the go/no-go task does not require a spatial discrimination, the best explanation for our findings is that the lesions impaired response working memory.
我们实验室之前的研究发现，虽然内侧隔区损伤会损害大鼠的操作性左右延迟交替任务，但该损伤也会促进大鼠在有线索的“去/不去”辨别任务中的表现，该任务线索与所需反应之间存在延迟。这些发现使我们认为，内侧隔区损伤损害了“反应”工作记忆，进而导致对刺激线索的注意力得到补偿性增强。如果这一假设成立，那么这些损伤应该会损害基于“反应”工作记忆的“去/不去”任务。当前的实验对这一假设进行了检验。大鼠（12只接受内侧隔区损伤，12只接受假手术）在离散试验操作性“去/不去”反应交替任务中接受测试。大鼠首先在没有延迟条件的情况下测试20天，然后在“去”和“不去”试验之间有15秒延迟的情况下测试35天。两组在无延迟条件下都熟练掌握了该任务，并且它们的最终表现（平均正确率约为85%）没有差异。然而，在延迟条件下，与对照组相比，损伤大鼠的表现明显受损。由于“去/不去”任务不需要空间辨别，我们的发现的最佳解释是这些损伤损害了反应工作记忆。
