Difference Between Accuracy- and Error-Related Brain Activity with Varying Memory Load in Maintenance Phase of Working Memory

摘要

Working memory (WM) has been one of the central themes in the area of cognitive neuroscience research for the past decades. WM refers to the temporary storage of information and a memory system which can carry on the processing of information. Memory load plays an important role in WM, through varying numbers of stimulus to realize the change of memory load. Functional magnetic resonance imaging (fMRI) as a common method is used to research the brain neural mechanism in varying memory load. Previous studies have compared memory load in each phase of WM, including encoding, maintenance and probing. In contrast to the previous ones, this study focused on comparing the difference between accuracy- and error-related brain activities with variable memory load during maintenance phase in WM. Fourteen healthy subjects participated in a variable load verbal of the Sternberg Item Recognition Task (SIRT). The results showed that response times (RTs) increased and accuracy decreased with memory load becoming higher. In addition, the dorsolateral prefrontal cortex (DLPFC) activation increased with WM load increased. In accuracy- versus (vs.) error-related condition, right para-hippocampus involved in the pattern of lower memory load, and right cerebellum lobule played a significant role in the condition of higher memory load. Contrary to the above condition, left superior temporal gyrus was obviously activated. These results indicated that the neural activity patterns during working memory maintenance, and showed that these patterns depended on accuracy- and error-related condition of with varying memory load.