一项研究发现了许多老年人面临的同时执行多重任务困难的神经基础。科研人员已经认同，随着人们衰老，许多人发现当一个新任务打断了原来的任务时，原来的任务就很难完成。Adam Gazzaley 及其同事使用了fMRI来找出参与一项多任务试验的20名60岁以上受试者的这种缺陷的神经基础。这组作者然后把这些结果与此前进行的20位较年轻的受试者参与的一项类似实验结果进行了比较。与较年轻的受试者相比，老年受试者在识别曾在一个显示器上展示给他们的自然场景方面的成功率更低，此时他们也被要求执行一个干扰任务，即报告在自然场景识别测试之前很短的时间里显示出的一张脸的性别和大约的年龄。根据这些受试者大脑的两个区域（视觉皮层和前额叶皮层）的连接模式，这组作者提出老年人在多任务方面的成功率较低并不是因为他们把更多的注意力分配给了那个干涉任务，而是因为他们更难以摆脱那个干扰任务并重新激活最初的任务的神经网络。这组作者说，特别是由于人们倾向于工作到更老，这些发现在衰老对认知性能的影响方面有意义。（生物谷Bioon.com）
生物谷推荐原文出处：
PNAS doi: 10.1073/pnas.1015297108
Deficit in switching between functional brain networks underlies the impact of multitasking on working memory in older adults
Wesley C. Clapp, Michael T. Rubens, Jasdeep Sabharwal, and Adam Gazzaley1
Abstract
Multitasking negatively influences the retention of information over brief periods of time. This impact of interference on working memory is exacerbated with normal aging. We used functional MRI to investigate the neural basis by which an interruption is more disruptive to working memory performance in older individuals. Younger and older adults engaged in delayed recognition tasks both with and without interruption by a secondary task. Behavioral analysis revealed that working memory performance was more impaired by interruptions in older compared with younger adults. Functional connectivity analyses showed that when interrupted, older adults disengaged from a memory maintenance network and reallocated attentional resources toward the interrupting stimulus in a manner consistent with younger adults. However, unlike younger individuals, older adults failed to both disengage from the interruption and reestablish functional connections associated with the disrupted memory network. These results suggest that multitasking leads to more significant working memory disruption in older adults because of an interruption recovery failure, manifest as a deficient ability to dynamically switch between functional brain networks.
