Langlais P J, Mandel R J, Mair R G
Department of Psychology, San Diego State University, CA 92162.
Behav Brain Res. 1992 Jun 8;48(2):177-85. doi: 10.1016/s0166-4328(05)80155-x.
Previous studies have shown that following an acute bout of pyrithiamine-induced thiamine deficiency (PTD) rats are impaired in learning appetitively and aversively motivated T-maze tasks. The present study examined if PTD-treated rats exhibit both anterograde and retrograde memory loss of an aversively motivated spatial navigation task. Histological examination revealed two consistent lesions in the PTD treated rats: a bilateral, symmetrical destruction of medial thalamus centered on the internal medullary lamina (IML), and a lesion of the medial nucleus of the mammillary body. In Experiment 1, control and recovered PTD rats were trained to find a hidden platform in a Morris water maze. PTD rats with the IML lesion were impaired in learning the water maze task but were eventually able to perform as well as controls and PTD animals without the IML lesion. In Experiment 2, half of the pretrained CT animals underwent thiamine deficiency (PTD2), were recovered, and subsequently were tested for retention of the platform location. The remaining CT animals and the PTD1 group were also tested for retention. No significant group differences were observed on any of the four postretention trials. When compared to their performance on the last four preretention trials, the performance of PTD1 and PTD2 animals with IML lesions were similar to those of the controls. These results demonstrate that acute thiamine deficiency in rats produces damage of medial thalamic and mammillary body nuclei, a mild anterograde learning deficit, but no loss of retrograde memory of the Morris water maze task.
先前的研究表明，在经历一次急性的硫胺素缺乏诱导（PTD）后，大鼠在学习食欲性和厌恶性动机的T迷宫任务时会受到损害。本研究考察了经PTD处理的大鼠是否在厌恶性动机的空间导航任务中表现出顺行性和逆行性记忆丧失。组织学检查发现，经PTD处理的大鼠有两个一致的损伤：以内髓板（IML）为中心的双侧对称性内侧丘脑破坏，以及乳头体内侧核的损伤。在实验1中，对照和恢复的PTD大鼠被训练在莫里斯水迷宫中找到一个隐藏平台。有IML损伤的PTD大鼠在学习水迷宫任务时受损，但最终能够与对照和没有IML损伤的PTD动物表现得一样好。在实验2中，一半预先训练的CT动物经历硫胺素缺乏（PTD2），恢复后，随后测试其对平台位置的记忆保持。其余的CT动物和PTD1组也进行了记忆保持测试。在四次记忆保持试验中的任何一次试验中，均未观察到显著的组间差异。与它们在最后四次预记忆试验中的表现相比，有IML损伤的PTD1和PTD2动物的表现与对照相似。这些结果表明，大鼠急性硫胺素缺乏会导致内侧丘脑和乳头体核的损伤，产生轻度的顺行性学习缺陷，但不会导致莫里斯水迷宫任务的逆行性记忆丧失。
