Kojima T, Onoe H, Hikosaka K, Tsutsui K, Tsukada H, Watanabe M
Department of Psychology, Tokyo Metropolitan Institute for Neuroscience, Musashidai 2-6, Fuchu, Tokyo, 183-8526, Japan.
Eur J Neurosci. 2007 Apr;25(8):2523-35. doi: 10.1111/j.1460-9568.2007.05504.x.
The lateral prefrontal cortex (LPFC) is important for working memory (WM) task performance. Neuropsychological and neurophysiological studies in monkeys suggest that the lateral prefrontal cortex is functionally segregated based on the working memory domain (spatial vs. non-spatial). However, this is not supported by most human neuroimaging studies, and the discrepancy might be due to differences in methods and/or species (monkey neuropsychology/physiology vs. human neuroimaging). We used positron emission topography to examine the functional segregation of the lateral prefrontal cortex of Japanese macaques (Macaca fuscata) that showed near 100% accuracy on spatial and non-spatial working memory tasks. Compared with activity during the non-working memory control tasks, the dorsolateral prefrontal cortex (DLPFC) was more active during the non-spatial, but not during the spatial, working memory task, although a muscimol microinjection into the dorsolateral prefrontal cortex significantly impaired the performance of both working memory tasks. A direct comparison of the brain activity between the two working memory tasks revealed no differences within the lateral prefrontal cortex, whereas the premotor area was more active during the spatial working memory task. Comparing the delay-specific activity, which did not include task-associated stimulus/response-related activity, revealed more spatial working memory-related activity in the posterior parietal and premotor areas, and more non-spatial working memory-related activity in the dorsolateral prefrontal cortex and hippocampus. These results suggest that working memory in the monkey brain is segregated based on domain, not within the lateral prefrontal cortex but rather between the posterior parietal-premotor areas and the dorsolateral prefrontal-hippocampus areas.
外侧前额叶皮质（LPFC）对工作记忆（WM）任务的执行很重要。对猴子的神经心理学和神经生理学研究表明，外侧前额叶皮质根据工作记忆领域（空间与非空间）在功能上是分离的。然而，大多数人类神经影像学研究并不支持这一点，这种差异可能是由于方法和/或物种的不同（猴子神经心理学/生理学与人类神经影像学）。我们使用正电子发射断层扫描来检查在空间和非空间工作记忆任务上表现出近100%准确率的日本猕猴（食蟹猴）外侧前额叶皮质的功能分离情况。与非工作记忆控制任务期间的活动相比，背外侧前额叶皮质（DLPFC）在非空间工作记忆任务期间更活跃，但在空间工作记忆任务期间并非如此，尽管向背外侧前额叶皮质微量注射蝇蕈醇会显著损害这两种工作记忆任务的表现。对两种工作记忆任务之间的大脑活动进行直接比较发现，外侧前额叶皮质内没有差异，而运动前区在空间工作记忆任务期间更活跃。比较不包括与任务相关的刺激/反应相关活动的延迟特定活动发现，顶叶后部和运动前区有更多与空间工作记忆相关的活动，背外侧前额叶皮质和海马体有更多与非空间工作记忆相关的活动。这些结果表明，猴子大脑中的工作记忆是根据领域分离的，不是在外侧前额叶皮质内，而是在顶叶后部 - 运动前区和背外侧前额叶 - 海马体区域之间。
