Buckner R L, Koutstaal W
Departments of Psychology, Anatomy and Neurobiology, and Radiology, Washington University, St. Louis, MO 63130, USA.
Proc Natl Acad Sci U S A. 1998 Feb 3;95(3):891-8. doi: 10.1073/pnas.95.3.891.
Human functional neuroimaging techniques provide a powerful means of linking neural level descriptions of brain function and cognition. The exploration of the functional anatomy underlying human memory comprises a prime example. Three highly reliable findings linking memory-related cognitive processes to brain activity are discussed. First, priming is accompanied by reductions in the amount of neural activation relative to naive or unprimed task performance. These reductions can be shown to be both anatomically and functionally specific and are found for both perceptual and conceptual task components. Second, verbal encoding, allowing subsequent conscious retrieval, is associated with activation of higher order brain regions including areas within the left inferior and dorsal prefrontal cortex. These areas also are activated by working memory and effortful word generation tasks, suggesting that these tasks, often discussed as separable, might rely on interdependent processes. Finally, explicit (intentional) retrieval shares much of the same functional anatomy as the encoding and word generation tasks but is associated with the recruitment of additional brain areas, including the anterior prefrontal cortex (right > left). These findings illustrate how neuroimaging techniques can be used to study memory processes and can both complement and extend data derived through other means. More recently developed methods, such as event-related functional MRI, will continue this progress and may provide additional new directions for research.
人类功能性神经成像技术提供了一种将大脑功能和认知的神经层面描述联系起来的有力手段。对人类记忆背后的功能解剖结构的探索就是一个典型例子。本文讨论了将与记忆相关的认知过程与大脑活动联系起来的三个高度可靠的发现。首先，与未经启动或未启动的任务表现相比，启动过程伴随着神经激活量的减少。这些减少在解剖学和功能上都是特定的，并且在感知和概念任务成分中都能发现。其次，允许后续有意识检索的言语编码与包括左下前额叶皮层和背侧前额叶皮层区域在内的高阶脑区的激活有关。这些区域在工作记忆和费力的单词生成任务中也会被激活，这表明这些通常被认为是可分离的任务可能依赖于相互依存的过程。最后，显性（有意）检索与编码和单词生成任务共享许多相同的功能解剖结构，但与额外脑区的激活有关，包括前额叶前部皮层（右侧>左侧）。这些发现说明了神经成像技术如何能够用于研究记忆过程，并且能够补充和扩展通过其他方式获得的数据。最近开发的方法，如事件相关功能磁共振成像，将继续推动这一进展，并可能为研究提供更多新的方向。
