Koch Kathrin, Wagner Gerd, von Consbruch Katrin, Nenadic Igor, Schultz Christoph, Ehle Christian, Reichenbach Jürgen, Sauer Heinrich, Schlösser Ralf
Department of Psychiatry, University of Jena, Philosophenweg 3, 07740 Jena, Germany.
Brain Res. 2006 Aug 30;1107(1):140-50. doi: 10.1016/j.brainres.2006.06.003. Epub 2006 Jul 14.
Several findings indicate that practice in working memory tasks leads to signal decreases in task-relevant regions. However, the precise dynamics underlying these signal decreases and how they are correlated with improvements in behavioral performance are still matters of debate. We used functional magnetic resonance imaging (fMRI) to assess the cerebral correlates of the practice-related transition from controlled to automatic processing for the retrieval of information maintained in working memory storage. Exponential signal decreases and increases were modeled as covariates of interest. In addition, a bivariate regression analysis on the change in BOLD signal for two a priori hypothesized prefrontal regions (VLPFC, DLPFC) and the change in behavioral performance was conducted to examine the relationship between practice-related changes in cerebral activation and performance. We found exponential practice-related signal decreases mainly in the right superior frontal gyrus/DLPFC (BA 8/9/46), the middle frontal gyrus bilaterally (BA 10/11), the left precentral gyrus (BA 4/6) and the dorsal part of the right anterior cingulate cortex (BA 32). An exponential signal increase was detectable in the posterior cingulate cortex adjacent to the corpus callosum. In addition, there was a correlation between the practice-related change in BOLD signal in the DLPFC (BA 8/9) and the practice-related change in behavioral performance. These results suggest that the transition from controlled to automatic working memory processing is associated with exponential signal decreases in task-relevant regions. The temporal changes in brain activation patterns could be attributed to enhanced efficiency of information processing as a result of cognitive practice.
多项研究结果表明，进行工作记忆任务的训练会导致与任务相关区域的信号减弱。然而，这些信号减弱背后的确切动态变化以及它们与行为表现改善之间的关联仍存在争议。我们使用功能磁共振成像（fMRI）来评估在工作记忆存储中维持的信息检索从受控加工到自动加工的与训练相关转变的大脑关联。指数型信号减弱和增强被建模为感兴趣的协变量。此外，对两个先验假设的前额叶区域（腹外侧前额叶皮层、背外侧前额叶皮层）的血氧水平依赖（BOLD）信号变化与行为表现变化进行了双变量回归分析，以检验大脑激活的训练相关变化与表现之间的关系。我们发现，与训练相关的指数型信号减弱主要出现在右侧额上回/背外侧前额叶皮层（BA 8/9/46）、双侧额中回（BA 10/11）、左侧中央前回（BA 4/6）以及右侧前扣带回皮层的背侧部分（BA 32）。在胼胝体附近的后扣带回皮层中可检测到指数型信号增强。此外，背外侧前额叶皮层（BA 8/9）中与训练相关的BOLD信号变化与行为表现的训练相关变化之间存在相关性。这些结果表明，从受控工作记忆加工到自动工作记忆加工的转变与任务相关区域的指数型信号减弱有关。大脑激活模式的时间变化可能归因于认知训练导致的信息处理效率提高。
