Trait and State Frontal Brain Asymmetry in Depression

描述（由申请人提供）：不对称的额叶脑活动有望成为抑郁症风险的标志。超过40项研究表明，静息额叶脑电图（EEG）的不对称性可能是一个指标的特质样素质，以情绪消极和行为退缩的模式来应对情绪状况。此外，静息额叶脑电图的不对称性将抑郁的个体--那些目前有症状的个体以及那些缓解的个体--与从未抑郁的个体区分开来。这些研究结果表明，额叶脑电图不对称是一个相关的抑郁发作，可能作为一个责任标记抑郁症的发展。这种标记可能具有预后和病因学价值，但叠加在性状样稳定性上的是波动，其作为评估或实验操纵的情绪的函数而变化。额叶脑电不对称的稳定性估计在0.60的范围内，这表明特质因素是相当大的，但评估的变化可能会限制不对称额叶脑活动作为抑郁症的特质样风险指标的效用。这些因素可能是本文献中少数不一致结果的基础。目前的建议是一个必要的步骤，在程序化调查的额叶脑电不对称作为一个潜在的风险指标抑郁症，通过评估三个不同的来源的变异性额叶脑电不对称：1）稳定的特质一致性在多个评估; 2）特定场合的波动，从一个评估到下一个;和，3）状态依赖性的变化在一个单一的评估。在四次访问中，特质休息以及状态操纵的额叶脑电图不对称性将在抑郁症和非抑郁症受试者进行评估。这个设计将使我们能够解决几个具体的目标，包括：1）评估的相对贡献的特质，场合，和状态变量在额叶脑电不对称性; 2）评估是否额叶脑电不对称的特点，表明它可能是有益的作为一个标记的风险，以重性抑郁症;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叶EEG不对称性的急性影响，因为药物作用在很大程度上尚未探索。次要目的是解决方法和治疗相关的问题，以及评估性别和月经周期的影响，可能缓和额叶脑电图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.