A balancing act of the brain: activations and deactivations driven by cognitive load

Brain and Behavior

Marie Arsalidou¹  Juan Pascual-Leone¹  Janice Johnson¹  Drew Morris² 

[1] Department of Psychology, York University, Toronto, Ontario, Canada;Diagnostic Imaging and Research Institute, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada

关键词: Default mode;    difficulty;    fMRI;    working memory;   

DOI  :  10.1002/brb3.128

来源: Wiley

【 摘 要 】

Abstract

The majority of neuroimaging studies focus on brain activity during performance of cognitive tasks; however, some studies focus on brain areas that activate in the absence of a task. Despite the surge of research comparing these contrasted areas of brain function, their interrelation is not well understood. We systematically manipulated cognitive load in a working memory task to examine concurrently the relation between activity elicited by the task versus activity during control conditions. We presented adults with six levels of task demand, and compared those with three conditions without a task. Using whole-brain analysis, we found positive linear relations between cortical activity and task difficulty in areas including middle frontal gyrus and dorsal cingulate; negative linear relations were found in medial frontal gyrus and posterior cingulate. These findings demonstrated balancing of activation patterns between two mental processes, which were both modulated by task difficulty. Frontal areas followed a graded pattern more closely than other regions. These data also showed that working memory has limited capacity in adults: an upper bound of seven items and a lower bound of four items. Overall, working memory and default-mode processes, when studied concurrently, reveal mutually competing activation patterns.

【 授权许可】

CC BY   
© 2013 The Authors. Brain and Behavior published by Wiley Periodicals, Inc.

Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.