A posteriori model validation for the temporal order of directed functional connectivity maps.
A posteriori model validation for the temporal order of directed functional connectivity maps.
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DOI：
10.3389/fnins.2015.00304
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发表时间：
2015
影响因子：
4.3
通讯作者：
Molenaar PC
中科院分区：
文献类型：
--
作者：
Beltz AM;Molenaar PC
神经定向功能连接图的时序的后验模型验证是罕见的。这是惊人的，因为需要残差之间序列独立性的模型经常被实现。当前研究的目的是（a）将后验模型验证程序（即，一步前预测误差的白色噪声测试结合基于拉格朗日乘数测试的用于修正图的决策标准），以及（B）演示该程序如何应用于单受试者模拟、单受试者任务相关和多受试者静息状态数据。通过统一结构方程模型族的方法确定定向功能连接，以映射组和个体水平的脑区域之间的同期和一阶滞后连接，同时结合外部输入，然后运行白色噪声测试。研究结果表明，验证程序成功地检测到未建模的顺序依赖残差和恢复高阶（大于一个）的模拟连接，该程序可以容纳任务相关的输入。研究结果还显示，滞后大于1存在于静息状态数据：与组级网络，只包含同期和一阶连接，44%的受试者需要二阶，个人水平的连接，以获得地图与白色噪声残差。结果具有广泛的方法相关性（例如，在定向功能连接性分析之后时间验证是必要的，因为未建模的高阶顺序依赖性的存在可能使参数估计有偏差）和实质性含义（例如，更高阶滞后在休息状态数据中可能是常见的）。
A posteriori model validation for the temporal order of neural directed functional connectivity maps is rare. This is striking because models that require sequential independence among residuals are regularly implemented. The aim of the current study was (a) to apply to directed functional connectivity maps of functional magnetic resonance imaging data an a posteriori model validation procedure (i.e., white noise tests of one-step-ahead prediction errors combined with decision criteria for revising the maps based upon Lagrange Multiplier tests), and (b) to demonstrate how the procedure applies to single-subject simulated, single-subject task-related, and multi-subject resting state data. Directed functional connectivity was determined by the unified structural equation model family of approaches in order to map contemporaneous and first order lagged connections among brain regions at the group- and individual-levels while incorporating external input, then white noise tests were run. Findings revealed that the validation procedure successfully detected unmodeled sequential dependencies among residuals and recovered higher order (greater than one) simulated connections, and that the procedure can accommodate task-related input. Findings also revealed that lags greater than one were present in resting state data: With a group-level network that contained only contemporaneous and first order connections, 44% of subjects required second order, individual-level connections in order to obtain maps with white noise residuals. Results have broad methodological relevance (e.g., temporal validation is necessary after directed functional connectivity analyses because the presence of unmodeled higher order sequential dependencies may bias parameter estimates) and substantive implications (e.g., higher order lags may be common in resting state data).