Mitchell Anna S, Gaffan David
Department of Experimental Psychology, Oxford University, Oxford OX1 3UD, United Kingdom.
J Neurosci. 2008 Jan 2;28(1):258-63. doi: 10.1523/JNEUROSCI.4922-07.2008.
Damage to the magnocellular mediodorsal thalamic nucleus (MDmc) in the human brain is associated with both retrograde and anterograde amnesia. In the present study we made selective neurotoxic MDmc lesions in rhesus monkeys and compared the effects of these lesions on memory acquisition and retrieval. Monkeys learned 300 unique scene discriminations preoperatively and retention was assessed in a one-trial preoperative retrieval test. Bilateral neurotoxic lesions of the MDmc, produced by 10 x 1 microl injections of a mixture of ibotenate and NMDA did not affect performance in the postoperative one-trial retrieval test. In contrast, new postoperative learning of a further 100 novel scene discriminations was substantially impaired. Thus, MDmc is required for new learning of scene discriminations but not for their retention and retrieval. This finding is the first evidence that MDmc plays a specific role in memory acquisition.
人类大脑中巨细胞丘脑背内侧核（MDmc）受损与逆行性和顺行性失忆均有关联。在本研究中，我们对恒河猴制造了选择性神经毒性MDmc损伤，并比较了这些损伤对记忆获取和提取的影响。猴子在术前学习了300种独特场景辨别任务，并在术前一次性提取测试中评估记忆保持情况。通过10次每次1微升的鹅膏蕈氨酸和N-甲基-D-天冬氨酸混合物注射所造成的MDmc双侧神经毒性损伤，并未影响术后一次性提取测试中的表现。相比之下，术后对另外100种新场景辨别的学习则受到显著损害。因此，MDmc对于新的场景辨别学习是必需的，但对于其记忆保持和提取并非必需。这一发现首次证明MDmc在记忆获取中发挥特定作用。
