Cognitive control is supported by a dynamic interplay of transient (i.e., trial-related) brain activation across fronto-parietal networks and sustained (i.e., block-related) activation across fronto-striatal networks. Older adults show disturbances in this dynamic functional recruitment. There is evidence suggesting that cognitive-control training may enable older adults to redistribute their brain activation across cortical and subcortical networks, which in turn can limit behavioral impairments. However, previous studies have only focused on spatial rather than on temporal aspects of changes in brain activation. In the present study, we examined training-related functional plasticity in old age by applying a hybrid fMRI design that sensitively tracks the spatio-temporal interactions underlying brain-activation changes. Fifty healthy seniors were assigned to a task-shifting training or an active-control group and their pretest/posttest activation-change maps were compared against 25 untrained younger adults. After training, older adults showed the same performance as untrained young adults. Compared to the control group, task-shifting training promoted proactive (i.e., early, cue-related) changes in transient mechanisms supporting the maintenance and top-down biasing of task-set representations in a specific prefrontal circuitry; reactive (i.e., late, probe-related) changes in transient mechanisms supporting response-selection processes in dissociable fronto-parietal networks; overall reductions of sustained activation in striatal circuits. Results highlight the importance of spatio-temporal interactions in training-induced neural changes in age.

中文翻译：

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老年人进行任务转移训练后脑活动动力学的可塑性。

跨额叶顶层网络的短暂（即与试验相关的）大脑激活与额叶纹状体网络的持续（即与块相关的）激活之间的动态相互作用，为认知控制提供了支持。老年人在这种动态的功能募集中表现出障碍。有证据表明，认知控制训练可以使老年人在大脑皮层和皮层下网络中重新分配他们的大脑活动，从而可以限制行为障碍。但是，以前的研究仅关注大脑激活变化的空间方面，而不是时间方面。在本研究中，我们通过应用混合功能磁共振成像设计来敏感地跟踪脑部激活变化背后的时空相互作用，从而研究了老年时与训练相关的功能可塑性。将五十名健康的老年人分配到任务轮换培训或一个主动对照组中，并将他们的测试前/测试后激活变化图与25位未经训练的年轻人进行比较。训练后，老年人表现出与未经训练的年轻人相同的表现。与对照组相比，任务转移培训促进了瞬态机制的主动（即早期，提示相关）变化，这些瞬变机制支持特定前额叶电路中任务集表示的维护和自上而下的偏见。在可分离的额顶网络中支持响应选择过程的瞬态机制中的反应性（即晚期，与探针相关）变化；总体上减少了纹状体回路中持续激活。结果突出了时空相互作用在训练引起的年龄神经变化中的重要性。