Mechanisms of Attentional Control Revealed by Temporal Fluctuations in Neural Activity

人眼收集的视觉信息比大脑可能处理的要多得多，因此，需要注意优先考虑相关的刺激，而忽略不相关的刺激。先前的研究表明，人类有能力自愿地将注意力引导到行为上重要的物体、特征或位置上，但他们也容易被显著的、无关的刺激不由自主地吸引注意力。在国家科学基金会的资助下，新汉普郡大学的安德鲁·B·莱伯博士正在开展研究，以了解人类如何在注意力的自愿和非自愿成分之间实现平衡。他的研究正在使用功能磁共振成像(FMRI)来阐明这一重要问题，解决两个具体目标。第一个目标是确定个体在施加自愿注意和经历非自愿注意的敏感性方面是否会随着时间的推移而波动。介绍了一种新的方法，其中跟踪反映在fMRI信号中的神经活动的基线波动，以便提前预测分心行为指数的时刻到时刻的波动。这种方法可以发现大脑中用于自愿和非自愿注意的区域。第二个目标是了解个体如何改变注意力的自愿和非自愿成分之间的平衡。一方面，他们可以使用增强过程，通过增强相关刺激特征的神经表征，从而减少无关刺激显著的影响。另一方面，他们可以使用一个压抑的过程，通过这个过程，一个已知的无关的分心事物可以被直接抑制。正在进行的实验正在确定参与克服分心的大脑区域是增强相关信息，还是抑制无关信息，还是两者兼而有之。忽略令人分心的信息对于成功完成日常任务至关重要，无论是走路还是开车，还是操作重型机械。该项目有助于更好地理解大脑如何克服视觉分心，以便进行健康的视觉处理。该项目还旨在帮助更好地了解与注意力相关的临床疾病，如阿尔茨海默病、注意力缺陷多动障碍(ADHD)和精神分裂症，所有这些疾病以前都与大脑活动和行为的异常波动有关。除了科学影响，该项目还在新汉普郡大学提供了宝贵的培训机会，标志着先进的人类神经科学技术的引入。研究生和本科生从事功能磁共振数据的收集和分析，他们通过在国际研究会议上发表报告和在同行评议期刊上发表文章来帮助广泛传播结果。这项研究丰富了大学更广泛的知识界，因为学生和教职员工受益于将研究整合到本科课程和高级研讨会中。

The human eyes collect vastly more visual information than the brain can possibly process, and consequently, attention is required to prioritize stimuli that are relevant while ignoring those that are not. Previous work has shown that humans possess the capacity to voluntarily direct attention to behaviorally important objects, features, or locations, but they are also susceptible to having their attention captured involuntarily by salient, irrelevant stimuli. With funding from the National Science Foundation, Andrew B. Leber, Ph.D., of the University of New Hampshire, is carrying out research to learn how humans achieve a balance between the voluntary and involuntary components of attention. His research is using functional magnetic resonance imaging (fMRI) to shed light on this important issue, addressing two specific aims. The first aim is to determine whether individuals fluctuate over time in exerting voluntary attention and experiencing susceptibility to involuntary attention. A novel methodological approach is introduced in which baseline fluctuations in neural activity reflected in the fMRI signal are tracked in order to predict in advance moment-to-moment fluctuations in behavioral indices of distractibility. This approach allows the discovery of brain regions used in voluntary and involuntary attention. The second aim is to understand how individuals can tip the balance between voluntary and involuntary components of attention. On the one hand, they can use a process of enhancement, by which the neural representation of relevant stimulus features is boosted, thereby reducing the impact of irrelevant stimulus salience. On the other hand, they can use a process of suppression, by which a known irrelevant distractor can be directly inhibited. The experiments being carried out are determining whether brain regions involved in overcoming distraction either enhance relevant information, suppress irrelevant information, or both. Ignoring distracting information is critical for successful completion of everyday tasks, from walking or driving to operating heavy machinery. This project is contributing to a greater understanding of how the brain overcomes visual distraction in order to allow healthy visual processing. The project also aims to contribute to efforts to better understand clinical disorders with an attention-related component, such as Alzheimer's disease, Attention Deficit Hyperactivity Disorder (ADHD), and Schizophrenia, all of which have previously been associated with abnormal fluctuations in brain activity and behavior. Beyond scientific impacts, this project provides valuable training opportunities at the University of New Hampshire, where it marks the introduction of advanced human neuroscience techniques. Graduate and undergraduate students engage in collection and analysis of fMRI data, and they assist in disseminating the results broadly, via presentation at international research conferences and publication in peer-reviewed journals. The research enriches the broader intellectual community at the University, as student and faculty colleagues benefit from the integration of the research into undergraduate courses and advanced seminars.