Cingulate activation increases dynamically with response speed under stimulus unpredictability
Cingulate activation increases dynamically with response speed under stimulus unpredictability
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DOI：
10.1093/cercor/bhl075
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发表时间：
2007-07-01
期刊：
影响因子：
3.7
通讯作者：
Stein, Elliot A.
中科院分区：
文献类型：
--
作者：
Hahn, Britta;Ross, Thomas J.;Stein, Elliot A.
认知的功能磁共振成像研究需要重复和一致地参与研究中的认知过程。激活通常被认为对特定的心理操作或状态造成负担，而试验之间的个体内表现差异通常被认为是误差方差。最近的一种分析方法假定，这些波动可以反映由特定试验类型征税的过程中的变化。在本研究中，参与者对4个外围位置中的1个随机呈现的目标做出反应。通过使用单个试验的反应时间(RT)的函数作为线性回归变量，在逐个试验的基础上识别其激活随RT变化的大脑区域。全脑分析显示，在RT较快的试验中，前扣带回、后扣带回和左角/颞上回更活跃，但仅当靶点位置不可预测时。在通过中央线索预测目标位置的试验中，没有发现这种关联。这些结果表明扣带回和角回在注意不可预测事件的动态调节中起作用。这与缺省网络的功能是一致的，缺省网络在没有自上而下的重点关注的情况下是活跃的，并被认为不断地为广泛和自发的信息收集提供资源。利用试验间表现的可变性可能特别适合于捕捉诸如刺激驱动的注意过程这样的自发和难以捉摸的现象。
Functional magnetic resonance imaging studies of cognition require repeated and consistent engagement of the cognitive process under investigation. Activation is generally averaged across trials that are assumed to tax a specific mental operation or state, whereas intraindividual variability in performance between trials is usually considered error variance. A more recent analysis approach postulates that these fluctuations can reflect variation in the very process taxed by the particular trial type. In the present study, participants responded to targets presented randomly in 1 of 4 peripheral locations. By employing a function of reaction time (RT) of individual trials as a linear regressor, brain regions were identified whose activation varied with RT on a trial-by-trial basis. Wholebrain analysis revealed that the anterior cingulate, posterior cingulate, and left angular/superior temporal gyri were more active in trials with faster RT but only when the target location was unpredictable. No such association was seen in trials where the target location was predicted by a central cue. These results suggest a role for the cingulate and angular gyri in the dynamic regulation of attention to unpredictable events. This is in accordance with the function of a default network that is active in the absence of top-down-focused attention and is thought to continuously provide resources for broad and spontaneous information gathering. Exploiting intertrial performance variability may be particularly suitable for capturing such spontaneous and elusive phenomena as stimulus-driven processes of attention.