Neuroscientists often use functional magnetic resonance imaging (fMRI) to infer effects of treatments on neural activity in brain regions. In a typical fMRI experiment, each subject is observed at several hundred time points. At each point, the blood oxygenation level dependent (BOLD) response is measured at 100,000 or more locations (voxels). Typically, these responses are modeled treating each voxel separately, and no rationale for interpreting associations as effects is given. Building on Sobel and Lindquist (J. Amer. Statist. Assoc. 109 (2014) 967–976), who used potential outcomes to define unit and average effects at each voxel and time point, we define and estimate both “point” and “cumulated” effects for brain regions. Second, we construct a multisubject, multivoxel, multirun whole brain causal model with explicit parameters for regions. We justify estimation using BOLD responses averaged over voxels within regions, making feasible estimation for all regions simultaneously, thereby also facilitating inferences about association between effects in different regions. We apply the model to a study of pain, finding effects in standard pain regions. We also observe more cerebellar activity than observed in previous studies using prevailing methods.

中文翻译：

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估计人脑功能研究中的因果效应：新模型，新方法和新估计

神经科学家经常使用功能磁共振成像（fMRI）来推断治疗对大脑区域神经活动的影响。在典型的功能磁共振成像实验中，在数百个时间点观察每个对象。在每个点，在100,000个或更多位置（体素）测量依赖于血液氧合水平（BOLD）的响应。通常，将这些响应建模为分别处理每个体素的模型，并且没有给出将关联解释为效果的理由。建立在索贝尔和林德奎斯特（J.阿米尔。统制，副教授。 109（2014）967–976），他使用潜在的结果来定义每个体素和时间点的单位和平均效果，我们定义并估计了大脑区域的“点”效果和“累计”效果。其次，我们构造了带有区域明确参数的多主体，多体素，多行程全脑因果模型。我们使用在区域内体素上平均的BOLD响应来证明估计的合理性，同时对所有区域进行可行的估计，从而也便于推断不同区域之间的效果之间的关联。我们将该模型应用于疼痛研究，在标准疼痛区域中发现效果。我们还观察到小脑活动比以前使用流行方法进行的研究要多。