Department of Radiology, Xuanwu Hospital, Capital Medical University, Beijing 100053, China.
Neurosci Lett. 2012 Aug 1;522(2):113-7. doi: 10.1016/j.neulet.2012.06.019. Epub 2012 Jun 16.
While our previous work suggests that the midazolam-induced memory impairment results from the inhibition of new association formation, little is known about the neural correlates underlying these effects beyond the effects of GABA agonists on the brain. We used arterial spin-labeling perfusion MRI to measure cerebral blood flow changes associated with the effects of midazolam on ability to learn arbitrary word-pairs. Using a double-blind, within-subject cross-over design, subjects studied word-pairs for a later cued-recall test while they were scanned. Lists of different word-pairs were studied both before and after an injection of either saline or midazolam. As expected, recall was severely impaired under midazolam. The contrast of MRI signal before and after midazolam administration revealed a decrease in CBF in the left dorsolateral prefrontal cortex (DLPFC), left cingulate gyrus and left posterior cingulate gyrus/precuneus. These effects were observed even after controlling for any effect of injection. A strong correlation between the midazolam-induced changes in neural activity and memory performance was found in the left DLPFC. These findings provide converging evidence that this region plays a critical role in the formation of new associations and that low functioning of this region is associated with anterograde amnesia.
虽然我们之前的工作表明咪达唑仑引起的记忆损伤是由于新的联想形成受到抑制，但除了 GABA 激动剂对大脑的影响之外，对于这些影响背后的神经相关性知之甚少。我们使用动脉自旋标记灌注 MRI 来测量与咪达唑仑对学习任意单词对能力的影响相关的血流变化。使用双盲、within-subject 交叉设计，在扫描时，受试者在学习单词对以备稍后的提示回忆测试。在注射生理盐水或咪达唑仑之前和之后，研究了不同单词对的列表。正如预期的那样，咪达唑仑会严重损害回忆。咪达唑仑给药前后 MRI 信号的对比显示，左背外侧前额叶皮层 (DLPFC)、左扣带回和左后扣带回/楔前叶的 CBF 下降。即使在控制了注射的任何影响后，仍然观察到这些影响。在左 DLPFC 中发现了神经活动和记忆表现之间的强烈相关性。这些发现提供了一致的证据，表明该区域在新联想的形成中起着关键作用，并且该区域的功能低下与顺行性遗忘有关。
