Trait and State Frontal Brain Asymmetry in Depression

描述(由申请者提供)：不对称的额部大脑活动有望成为抑郁症风险的标志。40多项研究表明，静息额脑电(EEG)的不对称性可以作为一种特质类素质的指标，以情绪消极和行为退缩的模式对情绪状况做出反应。此外，静息的额部脑电不对称性将抑郁症患者--那些目前有症状的人以及缓解中的人--与从未患抑郁症的人区分开来。这些发现表明，额部脑电不对称不仅仅是抑郁发作的相关性，还可能成为抑郁发展的易患标志。这样的标记物可能具有预后和病因学价值，但在类似特质的稳定性上叠加的是波动，这些波动随着评估的时机或实验中操纵的情绪而变化。对额部脑电不对称性稳定性的估计在0.60的范围内，这表明特质因素是重要的，但不同评估的差异可能会限制额部非对称性大脑活动作为抑郁症的特质样风险指标的用途。这些因素可能是这篇文献中少数不一致的发现的基础。通过评估额部脑电不对称性的三个不同的变异性来源：1)多个评估的稳定的特征一致性；2)从一个评估到下一个评估的特定场合的波动；以及，3)单一评估中的状态依赖变化，本提案代表了将额部脑电不对称性作为抑郁的潜在风险指标的程序性研究中的必要步骤。在四次访问中，抑郁和非抑郁受试者的特征休息以及状态操纵的额部脑电不对称性将被评估。这项设计将使我们能够解决几个特定的目标，包括：1)评估特征、时机和状态差异在额部脑电不对称中的相对贡献；2)评估额部脑电不对称是否具有可作为严重抑郁障碍风险标志的特征；以及3)评估广泛使用的选择性5-羟色胺再摄取抑制剂对额部脑电不对称的急性影响，因为药物效应在很大程度上尚未被探索。次要目的是解决方法学和治疗相关的问题，以及评估性别和月经周期的影响，这些影响可能缓和额叶脑电不对称和抑郁症之间的关系。

DESCRIPTION (provided by applicant): Asymmetrical frontal brain activity holds promise as a marker of risk for depression. Over 40 studies suggest that resting frontal electroencephalographic (EEG) asymmetry may serve as an indicator of a trait-like diathesis to respond to emotional situations with a pattern of emotional negativity and behavioral withdrawal. Moreover, resting frontal EEG asymmetry distinguishes depressed individuals -- those currently symptomatic as well those as in remission -- from never-depressed individuals. These findings suggest that frontal EEG asymmetry is more than a correlate of a depressive episode, potentially serving as a liability marker for the development of depression. Such a marker could have prognostic and etiological value, but superimposed on the trait-like stability are fluctuations that vary as a function of occasion of assessment or experimentally manipulated emotion. Estimates of the stability of frontal EEG asymmetry are in the range of.60, suggesting that trait factors are substantial, but that variation across assessments may limit the utility of asymmetrical frontal brain activity as a trait-like risk indicator for depression. Such factors may underlie the few inconsistent findings in this literature. The present proposal represents a necessary step in the programmatic investigation of frontal EEG asymmetry as a potential risk indicator for depression, by evaluating three distinct sources of variability in frontal EEG asymmetry: 1) Stable trait consistency across multiple assessments; 2) Occasion-specific fluctuations from one assessment to the next; and, 3) State-dependent changes within a single assessment. During four visits, trait resting as well as state manipulated frontal EEG asymmetry will be assessed in depressed and nondepressed subjects. This design will allow us to address several specific aims, including: 1) To assess the relative contributions of trait, occasion, and state variance in frontal EEG asymmetry; 2) To assess whether frontal EEG asymmetry has characteristics that suggest it may profitably serve as a marker of risk for major depressive disorder; and, 3) To assess the acute impact of a widely used selective serotonin reuptake inhibitor on frontal EEG asymmetry, as medication effects have been largely unexplored. Secondary aims address methodological and treatment-related questions, as well as assessing gender and menstrual cycle effects that may moderate the relationship between frontal EEG asymmetry and depression.