Integrating the neural and biochemical basis of attention in humans

整合人类注意力的神经和生化基础

• 批准号: RGPIN-2019-05690
• 负责人: Schmitz, Taylor
• 金额: $ 3.28万
• 依托单位: University of Western Ontario
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=688989
• 关键词: Integrating; neural; biochemical; basis; attention

Selective attention is a set of core operations in the brain that control the flow of behaviourally relevant information. Since the first demonstrations of a neural basis of attention, researchers have focused almost exclusively on how attention changes the firing rate of neuronsexpressed by the mean of their activity over experimental trials. However, driven by sophisticated new probes of neural activity in non-human animal models, our understanding of attention is changing dramatically.******From this recent work, a novel mechanistic basis of attention has emerged, which is invisible to traditional approaches of averaging neural activity over trials. In addition to increasing a neuron's average responses, attention can reduce the variance, or noise, of a neuron's trial-to-trial responses. Attention-driven reductions in noise can have large effects on population neural activity because an individual neuron's noise is often correlated with the noise of neighboring neurons. By reducing shared noise in a population, attention can dramatically influence how much information is represented at any given time. Intriguingly, one of the brain's core neuromodulatory chemicalsacetylcholineinduces rapid changes in the noise correlations among neurons which closely mimic the effects of directed attention.******Together, these discoveries reveal a potent mechanism of attention expressed in the noise of population coding and its neurochemical basis. However, the invasive recording methods used to advance these discoveries are not feasible in humans. As a result, cross-species translation has slowed. This is a big problem. Current non-invasive probes of population activity, such as functional magnetic resonance imaging (fMRI), almost exclusively rely on trial-averaging methods. Large-scale effects of attention on population noise are therefore neglected in human research despite their fundamental role in cortical information processing. Moreover, because the most commonly used neuroimaging techniques, such as fMRI and EEG, are not sensitive to the brain's neurochemical environment, our understanding of the links between cognition and neuromodulation in humans remains very basic. ******My lab will examine the mechanistic basis of neuronal noise using human in vivo neuroimaging in order to translate and extend recent findings from non-human animal research. Are the mass neuronal responses indexed by fMRI sensitive to attention-driven changes in noise correlation? If so, how do attention-driven changes in noise correlation relate to the amount of information carried in the population code? Is cortical cholinergic modulation detectable with non-invasive imaging probes such as 1H magnetic resonance spectroscopy? If so, do attention-driven changes in noise correlation rely on cholinergic modulation? My program of research will develop novel human neuroimaging methods to triangulate the links among directed attention, cholinergic modulation and population coding. **

选择性注意是大脑中控制行为相关信息流动的一组核心操作。自从注意力的神经基础首次被证明以来，研究人员几乎完全集中在注意力如何改变神经元的放电率上，这些神经元的放电率是通过实验测试的平均活动来表达的。然而，在非人类动物模型神经活动的复杂新探针的推动下，我们对注意力的理解正在发生巨大变化。从最近的这项工作中，注意力的一个新的机械基础已经出现，这是传统的平均神经活动的方法所看不到的。除了增加神经元的平均反应外，注意力还可以减少神经元试验间反应的方差或噪音。注意力驱动的噪声减少可以对群体神经活动产生很大的影响，因为单个神经元的噪声通常与相邻神经元的噪声相关。通过减少群体中的共享噪音，注意力可以显著影响在任何给定时间内表示的信息量。有趣的是，大脑的核心神经调节化学物质之一乙酰胆碱（acetylcholine）会诱导神经元之间的噪音相关性发生快速变化，这与定向注意的效果非常相似。这些发现共同揭示了群体编码噪音及其神经化学基础中表达的有效注意力机制。然而，用于推进这些发现的侵入性记录方法在人类中是不可行的。因此，跨物种翻译已经放缓。这是一个大问题。目前非侵入性的人口活动的探针，如功能性磁共振成像（fMRI），几乎完全依赖于试验平均法。因此，在人类研究中，注意力对群体噪声的大规模影响被忽视了，尽管它们在皮层信息处理中起着重要作用。此外，由于最常用的神经成像技术，如fMRI和EEG，对大脑的神经化学环境不敏感，我们对人类认知和神经调节之间联系的理解仍然非常基本。 ** 我的实验室将使用人类体内神经成像来研究神经元噪声的机制基础，以便翻译和扩展非人类动物研究的最新发现。功能磁共振成像显示的大量神经元反应对注意力驱动的噪声相关性变化敏感吗？如果是这样的话，注意力驱动的噪声相关性变化与人口代码中携带的信息量有什么关系？皮质胆碱能调节是否可通过非侵入性成像探针（如1H磁共振波谱）检测？如果是这样的话，注意力驱动的噪声相关性变化是否依赖于胆碱能调制？我的研究计划将开发新的人类神经成像方法，以三角测量定向注意力，胆碱能调节和群体编码之间的联系。**