Petit L, Courtney S M, Ungerleider L G, Haxby J V
Laboratory of Brain and Cognition, National Institute of Mental Health, Bethesda, Maryland 20892-1366, USA.
J Neurosci. 1998 Nov 15;18(22):9429-37. doi: 10.1523/JNEUROSCI.18-22-09429.1998.
We have taken advantage of the temporal resolution afforded by functional magnetic resonance imaging (fMRI) to investigate the role played by medial wall areas in humans during working memory tasks. We demarcated the medial motor areas activated during simple manual movement, namely the supplementary motor area (SMA) and the cingulate motor area (CMA), and those activated during visually guided saccadic eye movements, namely the supplementary eye field (SEF). We determined the location of sustained activity over working memory delays in the medial wall in relation to these functional landmarks during both spatial and face working memory tasks. We identified two distinct areas, namely the pre-SMA and the caudal part of the anterior cingulate cortex (caudal-AC), that showed similar sustained activity during both spatial and face working memory delays. These areas were distinct from and anterior to the SMA, CMA, and SEF. Both the pre-SMA and caudal-AC activation were identified by a contrast between sustained activity during working memory delays as compared with sustained activity during control delays in which subjects were waiting for a cue to make a simple manual motor response. Thus, the present findings suggest that sustained activity during working memory delays in both the pre-SMA and caudal-AC does not reflect simple motor preparation but rather a state of preparedness for selecting a motor response based on the information held on-line.
我们利用功能磁共振成像（fMRI）提供的时间分辨率，来研究人类在工作记忆任务期间内侧壁区域所起的作用。我们划定了在简单手动运动期间激活的内侧运动区域，即辅助运动区（SMA）和扣带运动区（CMA），以及在视觉引导的眼球跳动运动期间激活的区域，即辅助眼区（SEF）。我们确定了在空间和面部工作记忆任务期间，相对于这些功能标志，内侧壁在工作记忆延迟期间持续活动的位置。我们识别出两个不同的区域，即前辅助运动区（pre-SMA）和前扣带回皮质的尾部（caudal-AC），它们在空间和面部工作记忆延迟期间均表现出相似的持续活动。这些区域与SMA、CMA和SEF不同且位于其前方。通过比较工作记忆延迟期间的持续活动与对照延迟期间的持续活动（即受试者等待提示以做出简单手动运动反应时的持续活动）之间的差异，识别出了前辅助运动区和尾侧前扣带回的激活。因此，目前的研究结果表明，前辅助运动区和尾侧前扣带回在工作记忆延迟期间的持续活动并非反映简单的运动准备，而是基于在线保存的信息选择运动反应的一种准备状态。
