Department of Radiation Sciences, Umeå Center for Functional Brain Imaging, Umeå University, Umeå, Sweden.
Department of Integrative Medical Biology, Umeå University, Umeå, Sweden.
Brain Behav. 2021 Feb;11(2):e01987. doi: 10.1002/brb3.1987. Epub 2020 Dec 9.
Rewarding and punishing stimuli elicit BOLD responses in the affective division of the striatum. The responses typically traverse from the affective to the associative division of the striatum, suggesting an involvement of associative processes during the modulation of stimuli valance. In this study, we hypothesized that fMRI responses to rewards versus punishments in a guessing card game can be disassociated into two functional component processes that reflect the convergence of limbic and associative functional networks in the ventral striatum.
We used fMRI data of 175 (92 female) subjects from the human connectome project´s gambling task, working memory task, and resting-state scans. A reward > punish contrast identified a ventral striatum cluster from which voxelwise GLM parameter estimates were entered into a k-means clustering algorithm. The k-means analysis supported separating the cluster into two spatially distinct components. These components were used as seeds to investigate their functional connectivity profile. GLM parameter estimates were extracted and compared from the task contrasts reward > punish and 2-back > 0-back from two ROIs in the ventral striatum and one ROI in hippocampus.
The analyses converged to show that a superior striatal component, coupled with the ventral attention and frontal control networks, was responsive to both a modulation of cognitive control in working memory and to rewards, whereas the most inferior part of the ventral striatum, coupled with the limbic and default mode networks including the hippocampus, was selectively responsive to rewards.
We show that the fMRI response to rewards in the ventral striatum reflects a mixture of component processes of reward. An inferior ventral striatal component and hippocampus are part of an intrinsically coupled network that responds to reward-based processing during gambling. The more superior ventral striatal component is intrinsically coupled to networks involved with executive functioning and responded to both reward and cognitive control demands.
奖赏和惩罚刺激会引起纹状体情感分区的 BOLD 反应。这些反应通常从情感分区到纹状体的联合分区传递，表明在调节刺激效价时涉及到联合过程。在这项研究中，我们假设在猜测纸牌游戏中，奖励与惩罚的 fMRI 反应可以分为两个功能成分过程，反映了边缘和关联功能网络在腹侧纹状体中的融合。
我们使用了人类连接组计划赌博任务、工作记忆任务和静息状态扫描的 175 名（92 名女性）受试者的 fMRI 数据。奖励>惩罚对比确定了一个腹侧纹状体簇，从中提取体素水平 GLM 参数估计值，并将其输入到 k-均值聚类算法中。k-均值分析支持将该簇分为两个空间上不同的成分。这些成分被用作种子来研究它们的功能连接模式。从腹侧纹状体的两个 ROI 和海马体的一个 ROI 中提取并比较了任务对比奖励>惩罚和 2 回>0 回的 GLM 参数估计值。
分析结果表明，一个高级纹状体成分与腹侧注意力和前额叶控制网络相结合，对工作记忆中的认知控制调节和奖励都有反应，而腹侧纹状体最下部与边缘和默认模式网络（包括海马体）相结合，仅对奖励有反应。
我们表明，腹侧纹状体中奖励的 fMRI 反应反映了奖励的混合成分过程。腹侧纹状体下部和海马体是一个内在耦合网络的一部分，该网络在赌博时对基于奖励的处理有反应。更高级的腹侧纹状体成分与涉及执行功能的网络内在耦合，并对奖励和认知控制需求都有反应。
