Neural Mechanisms of Motivational Influences on Perceptual Decision-Making

项目总结。随着时间的推移，整合感觉信息以指导适应行为的能力是一种 在精神疾病和神经障碍中被破坏的健康认知的重要组成部分。 众所周知，激励性突显会偏向感觉加工，并导致知觉决策中的系统性错误。 过去的研究表明，错误可以通过增强对动机的神经反应来驱动 想要的感知特征，但这种增强背后的神经机制没有得到充分说明。 蓝斑去甲肾上腺素(LC-NE)系统调节神经对感觉刺激的反应，是 能够很好地在知觉决策中发挥激励作用。拟议的研究将使用小说 经颅磁刺激(TMS)的LC成像方法和神经活动的因果操作 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，在这项任务中，他们的动机是看到一个感知 另一名患者正在接受功能磁共振成像(FMRI)。之前的工作面临着重大的 由于其体积小且位置的个体差异，使用功能磁共振成像可靠地测量LC信号面临挑战。 因此，AIM 1将使用最近开发的神经黑色素敏感成像序列来定位个体的LC 参与者并评估LC活动如何跟踪感觉表征的增强或抑制 使用多体素图案分析(MVPA)进行解码。这项拟议的研究将测试两种假设的机制。 这使得LC-NE系统能够选择性地增强所需知觉的神经表征：1)放大 通过神经增益的变化对所需特征的神经反应以及2)抑制对较少的神经反应 通过背外侧前额叶皮质(DLPFC)增加对感觉皮质的抑制，从而实现理想的功能。 然后，AIM 2将在参与者在MRI扫描仪中执行任务之前使用TMS扰乱DLPFC功能。 如果感觉表征的动机效应因果性依赖于DLPFC，则外源性干扰 DLPFC将减少甚至消除这些影响。这些结果将因此提供因果证据，证明 DLPFC调节知觉决策中的动机偏向。 这项拟议的研究将解决我们对动机如何形成的理解上的一个根本差距。 感官处理和知觉决策。从这些研究中获得的知识将为 为未来研究知觉决策缺陷的动机基础奠定基础 有病的大脑状态。拟议的研究还提供了LC成像和TMS方面的培训，这些创新工具 将允许表征和操纵构成各种动机-认知的神经回路 互动。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， 包括记忆加工、学习和推理。因此，拟议的研究提供了第一个但至关重要的 制定一项研究计划，研究动机对认知过程的影响。

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.