Neural Mechanisms of Motivational Influences on Perceptual Decision-Making

项目摘要。随着时间的推移，整合感官信息以指导适应行为的能力是一种 健康认知的重要组成部分，在精神疾病和神经系统疾病中被破坏。 动机显著性会使感觉加工产生偏差，导致知觉决策中的系统性错误。 过去的研究表明，错误可能是由神经反应的增强驱动的， 理想的感知特征，但这种增强的神经机制是不够的。 蓝斑去甲肾上腺素（LC-NE）系统调节神经对感觉刺激的反应， 能够很好地调节对感知决策的激励作用。这项研究将使用新的 LC成像方法和使用经颅磁刺激（TMS）的神经活动的因果操纵， 研究LC-NE系统在调节知觉决策中的动机偏差中的作用。 参与者将执行一项视觉分类任务，在该任务中，他们被激励去看一个被接受者。 另一个在接受功能性磁共振成像（fMRI）时。之前的工作面临着重大的挑战， 由于LC信号的小尺寸和其位置的个体可变性，使用fMRI可靠地测量LC信号面临挑战。 因此，目的1将使用最近开发的神经黑素敏感成像序列来定位个体中的LC 参与者，并评估LC活动如何跟踪感觉表征的增强或抑制 使用多像素模式分析（MVPA）解码。这项研究将测试两种假设的机制 这允许LC-NE系统选择性地增强期望感知的神经表征：1）放大 通过神经增益的变化对期望特征的神经响应，以及2）抑制对较少特征的神经响应， 通过背外侧前额叶皮层（DLPFC）增加对感觉皮层的抑制来实现期望的特征。 然后，目标2将在参与者在MRI扫描仪中执行任务之前使用TMS破坏DLPFC功能。 如果动机对感觉表征的影响是因果依赖于DLPFC，那么外源性干扰 DLPFC将减少甚至消除这些影响。因此，这些结果将提供因果证据， DLPFC调节知觉决策中的动机偏差。 这项拟议中的研究将解决我们对动机如何形成的理解中的一个根本性空白 感觉处理和知觉决策。从这些研究中获得的知识将奠定 未来工作的基础，调查在知觉决策缺陷的动机基础 病态的大脑状态拟议的研究还提供了LC成像和TMS的培训，这些创新工具 将允许表征和操纵神经回路，这些神经回路是各种动机认知的基础。 交互.未来的工作将使用这些方法来探索其他认知领域的动机偏见， 包括记忆处理、学习和推理。因此，拟议的研究提供了一个第一个但至关重要的 这是研究动机对认知过程影响的一个研究项目。

PROJECT SUMMARY. The ability to integrate sensory information over time to guide adaptive behavior is a critical component of healthy cognition that is disrupted in psychiatric illnesses and neurological disorders. Motivational salience is known to bias sensory processing and lead to systematic errors in perceptual decisions. Past work has shown that errors can be driven by the enhancement of neural responses to motivationally desirable perceptual features, but the neural mechanisms that underlie this enhancement are underspecified. The locus coeruleus norepinephrine (LC-NE) system modulates neural responsivity to sensory stimuli, and is well-positioned to mediate motivational effects on perceptual decisions. The proposed research will use novel LC imaging methods and causal manipulation of neural activity using transcranial magnetic stimulation (TMS) to investigate the role of the LC-NE system in mediating motivational biases in perceptual decision-making. Participants will perform a visual categorization task where they are motivated to see one percept over another while undergoing functional magnetic resonance imaging (fMRI). Prior work has faced significant challenges in reliably measuring LC signal using fMRI due to its small size and individual variability in its location. Aim 1 will thus use recently developed neuromelanin-sensitive imaging sequences to localize the LC in individual participants and assess how LC activity tracks the enhancement or suppression of sensory representations decoded using multivoxel pattern analysis (MVPA). The proposed study will test two hypothesized mechanisms that allow the LC-NE system to selectively enhance the neural representation of desirable percepts: 1) amplifying neural responses to desirable features via changes in neural gain and 2) suppressing neural responses to less desirable features by increasing inhibition to sensory cortices via the dorsolateral prefrontal cortex (DLPFC). Aim 2 will then use TMS to disrupt DLPFC function prior to participants performing the task in the MRI scanner. If motivational effects on sensory representations are causally dependent on the DLPFC, exogenously perturbing DLPFC will reduce or even eliminate these effects. These results will thus provide causal evidence that the DLPFC modulates motivational biases in perceptual decision-making. The proposed research will address a fundamental gap in our understanding of how motivation shapes sensory processing and perceptual decision-making. The knowledge gained from these studies will lay the foundation for future work investigating the motivational bases of deficits in perceptual decision-making in diseased brain states. The proposed research also affords training in LC imaging and TMS, innovative tools that will allow the characterization and manipulation of neural circuits that underlie various motivation-cognition interactions. Future work will use these methods to probe motivational biases in other cognitive domains, including memory processing, learning and reasoning. The proposed research thus provides a first but crucial step in developing a research program to investigate motivational influences on cognitive processes.