Central Institute of Mental Health, Medical Faculty Mannheim/Heidelberg, Department of Psychiatry and Psychotherapy, 68159 Mannheim, Germany.
J Neurosci. 2013 Sep 4;33(36):14526-33. doi: 10.1523/JNEUROSCI.0631-13.2013.
Electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) have been used to study the neural correlates of reward anticipation, but the interrelation of EEG and fMRI measures remains unknown. The goal of the present study was to investigate this relationship in response to a well established reward anticipation paradigm using simultaneous EEG-fMRI recording in healthy human subjects. Analysis of causal interactions between the thalamus (THAL), ventral-striatum (VS), and supplementary motor area (SMA), using both mediator analysis and dynamic causal modeling, revealed that (1) THAL fMRI blood oxygenation level-dependent (BOLD) activity is mediating intermodal correlations between the EEG contingent negative variation (CNV) signal and the fMRI BOLD signal in SMA and VS, (2) the underlying causal connectivity network consists of top-down regulation from SMA to VS and SMA to THAL along with an excitatory information flow through a THAL→VS→SMA route during reward anticipation, and (3) the EEG CNV signal is best predicted by a combination of THAL fMRI BOLD response and strength of top-down regulation from SMA to VS and SMA to THAL. Collectively, these findings represent a likely neurobiological mechanism mapping a primarily subcortical process, i.e., reward anticipation, onto a cortical signature.
脑电图 (EEG) 和功能磁共振成像 (fMRI) 已被用于研究奖励预期的神经相关性，但 EEG 和 fMRI 测量之间的相互关系尚不清楚。本研究的目的是使用健康人类受试者的同步 EEG-fMRI 记录，在一个成熟的奖励预期范式中研究这种关系。使用中介分析和动态因果建模分析丘脑 (THAL)、腹侧纹状体 (VS) 和补充运动区 (SMA) 之间的因果相互作用，结果表明：(1)THAL fMRI 血氧水平依赖 (BOLD) 活动介导了 EEG 条件负变 (CNV) 信号和 SMA 与 VS 中的 fMRI BOLD 信号之间的模态间相关性；(2)潜在的因果连通网络包括来自 SMA 到 VS 和 SMA 到 THAL 的自上而下调节，以及在奖励预期期间通过 THAL→VS→SMA 途径的兴奋性信息流；(3)EEG CNV 信号可以通过 THAL fMRI BOLD 反应以及 SMA 到 VS 和 SMA 到 THAL 的自上而下调节的强度来最佳预测。总之，这些发现代表了一种可能的神经生物学机制，将主要的皮质下过程（即奖励预期）映射到皮质特征上。
