Smart Ageing International Research Center, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan.
PLoS One. 2012;7(1):e30579. doi: 10.1371/journal.pone.0030579. Epub 2012 Jan 23.
The difference between the speed of simple cognitive processes and the speed of complex cognitive processes has various psychological correlates. However, the neural correlates of this difference have not yet been investigated. In this study, we focused on working memory (WM) for typical complex cognitive processes. Functional magnetic resonance imaging data were acquired during the performance of an N-back task, which is a measure of WM for typical complex cognitive processes. In our N-back task, task speed and memory load were varied to identify the neural correlates responsible for the difference between the speed of simple cognitive processes (estimated from the 0-back task) and the speed of WM. Our findings showed that this difference was characterized by the increased activation in the right dorsolateral prefrontal cortex (DLPFC) and the increased functional interaction between the right DLPFC and right superior parietal lobe. Furthermore, the local gray matter volume of the right DLPFC was correlated with participants' accuracy during fast WM tasks, which in turn correlated with a psychometric measure of participants' intelligence. Our findings indicate that the right DLPFC and its related network are responsible for the execution of the fast cognitive processes involved in WM. Identified neural bases may underlie the psychometric differences between the speed with which subjects perform simple cognitive tasks and the speed with which subjects perform more complex cognitive tasks, and explain the previous traditional psychological findings.
简单认知过程的速度与复杂认知过程的速度之间的差异具有多种心理相关性。然而，这种差异的神经相关性尚未得到研究。在这项研究中，我们专注于工作记忆（WM）作为典型的复杂认知过程。在执行 N-back 任务期间采集了功能磁共振成像数据，N-back 任务是对典型复杂认知过程的 WM 进行的测量。在我们的 N-back 任务中，改变了任务速度和记忆负荷，以确定负责简单认知过程速度（从 0-back 任务估计）与 WM 速度之间差异的神经相关性。我们的研究结果表明，这种差异的特征在于右侧背外侧前额叶皮层（DLPFC）的激活增加，以及右侧 DLPFC 与右侧顶叶上回之间的功能相互作用增加。此外，右侧 DLPFC 的局部灰质体积与参与者在快速 WM 任务中的准确性相关，而准确性又与参与者智力的心理计量学测量相关。我们的研究结果表明，右侧 DLPFC 及其相关网络负责执行与 WM 相关的快速认知过程。所确定的神经基础可能是主体执行简单认知任务的速度与主体执行更复杂认知任务的速度之间的心理计量学差异的基础，并解释了先前的传统心理学发现。
