Behavioral and functional MRI study of attention shift in human verbal working memory.
The tripartite model of memory proposed the requirement of attentional switching when accessing different items in working memory [J. Exp. Psychol. Learn. Mem. Cogn. 27 (2001) 817]. This internal focus of attention is limited to just one item and the switching process is time-consuming [Mem. Cogn. 26 (1998) 263]. In the current study, given a three-digit list stored in working memory, we found that it took longer to shift attention in the direction of "Upstream" than "Downstream", and that each shift was a "single step" process. To investigate the neural basis of this type of attention switching, we performed a functional MRI study. The results revealed that at least three important brain areas are involved, including the left dorsal lateral prefrontal cortex, the cingulate gyrus, and the medial occipital cortex. These areas all showed greater activation in the attention shift condition compared to control conditions of no (or decreased) attention shift requirements. In addition, the hemodynamic activities in these areas are highly correlated, suggesting a strong functional connectivity between them. Taken together with evidence from several recent investigations, our results suggest that these areas each play an important and specific role in collaboratively supporting the function of attention shift in working memory.
Li
Zhi Hao
ZH
Department of Neurobiology and Biophysics, University of Science and Technology of China, Anhui 230027, Hefei, PR China.
Sun
Xi Wen
XW
Wang
Zhao Xin
ZX
Zhang
Xiao Chu
XC
Zhang
Da Ren
DR
He
Sheng
S
Hu
Xiao Ping
XP
D000293:Adolescent; D000328:Adult; D001288:Attention / Q000502:physiology*; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000502:physiology*; D004193:Discrimination Learning / Q000502:physiology; D005260:Female; D006179:Gyrus Cinguli / Q000502:physiology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology*; D009415:Nerve Net / Q000502:physiology; D009778:Occipital Lobe / Q000502:physiology; D010153:Paired-Associate Learning / Q000502:physiology*; D010364:Pattern Recognition, Visual / Q000502:physiology*; D017397:Prefrontal Cortex / Q000502:physiology; D011340:Problem Solving / Q000502:physiology; D011597:Psychomotor Performance / Q000502:physiology; D011930:Reaction Time / Q000502:physiology; D012691:Serial Learning / Q000502:physiology*