Neuronal substrates underlying the construction of value in humans

人类价值构建的神经元基质

• 批准号: 2318899
• 负责人: John O'Doherty
• 金额: $ 80万
• 依托单位: California Institute of Technology
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-10-01 至 2026-09-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2318899&HistoricalAwards=false
• 关键词: Neuronal; substrates; underlying; construction; value

How do our personal preferences arise? We all have a multitude of preferences and a sense of our own individual taste – but why do we come to like some things and not like others? For instance, why might a person like potato chips but not like popcorn, pop music rather than country-western, baseball rather than basketball, or come to like a representational painting by Rembrandt, but dislike abstract, modern art of Jackson Pollock? The major question we are addressing in this project is how are our preferences formed in the brain? The researchers aim to test a theory that the brain relies on “features” of objects which are the elements that make up an object – such as the ingredients in a food item, or the color, shapes and textures in a painting, in order to make a decision about how much something is liked or not. The hypothesis is that the brain cells (neurons) respond to these elementary features of an object, and that other neurons integrate over these features to form an overall preference judgment. To test for this, the responses of neurons are recorded directly from the human brain, while people make simple judgements about how much they like a variety of items including food, visual art and even clothing items. This research is made possible because of safe technological advances in brain surgery, and the generosity of patients who are being treated for intractable epilepsy. Prior to brain surgery to remove the epileptic brain tissue, patients have small electrodes temporarily placed into their brain to locate their seizures as part of their treatment. These patients are often willing to volunteer to take part in research studies, yielding a rare opportunity to measure electrical activity from neurons directly. Understanding how neurons in our brain form our preferences could help us better understand how people make decisions in the real world.While value signals are known to be encoded in the brain, a fundamental question remains about how such signals come to be computed in the first place. The major hypothesis to be tested in this project is that value signals for stimuli ranging from foods to consumer goods through to art, are constructed by the brain in a dynamic fashion by integrating over the component features or attributes of a stimulus. While a number of prior studies have examined value construction using neuroimaging techniques (such as functional magnetic resonance imaging or fMRI), insights can only be gained over the spatiotemporal resolution of the technique, which cannot measure single cells. As a consequence, little is known about how stimulus features are represented by individual cells and integrated to compute an overall stimulus-value. Here, this limitation can be overcome through the use of intracranial recordings in human epilepsy patients while they perform three different tasks probing value construction. The research focuses on neuronal populations in the three key parts of the value network in the brain: the amygdala, lateral orbitofrontal, and ventromedial prefrontal cortex. The spatial resolution of these methods enables insight into how individual features are represented at the neuronal level, while the temporal resolution allows us to identify the temporal dynamics by which features are actively integrated to yield an overall value signal. Features in the amygdala and lateral orbitofrontal cortex are hypothesized to be integrated to yield value signals in the ventromedial prefrontal cortex. Furthermore, the research aims to address the means by which value signals are altered following a change in one’s overall goals, comparing a model in which features are modulated directly by a change in context, against an alternative in which the connectivity between feature neurons and value coding neurons are modulated by goal context, yet feature representations remain unchanged. This project promises to yield fundamental mechanistic insights into the neural computations underlying the production of value signals in the human brain, and the origin and neural basis of our individual preferences, which in turn serve a fundamental role in guiding human decision-making.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

我们的个人偏好是如何产生的？我们都有多种偏好和个人品味——但为什么我们会喜欢某些东西而不喜欢另一些东西呢？例如，为什么一个人可能喜欢薯片而不喜欢爆米花，喜欢流行音乐而不喜欢西部乡村音乐，喜欢棒球而不喜欢篮球，或者喜欢伦勃朗的具象绘画，但不喜欢杰克逊·波洛克的抽象现代艺术？我们在这个项目中要解决的主要问题是我们的偏好是如何在大脑中形成的？研究人员旨在测试一种理论，即大脑依赖于物体的“特征”，即构成物体的元素——例如食物中的成分，或绘画中的颜色、形状和纹理，来决定喜欢或不喜欢某物。假设是脑细胞（神经元）对物体的这些基本特征做出反应，并且其他神经元对这些特征进行整合以形成整体偏好判断。为了测试这一点，直接从人脑记录神经元的反应，同时人们对自己对各种物品（包括食物、视觉艺术甚至服装）的喜欢程度做出简单的判断。这项研究之所以成为可能，是因为脑外科手术的安全技术进步以及正在接受难治性癫痫治疗的患者的慷慨解囊。在进行脑部手术切除癫痫脑组织之前，患者的大脑中会暂时放置小电极，以定位癫痫发作的位置，作为治疗的一部分。这些患者通常愿意自愿参加研究，从而提供了直接测量神经元电活动的难得机会。了解大脑中的神经元如何形成我们的偏好可以帮助我们更好地了解人们如何在现实世界中做出决策。虽然已知价值信号在大脑中进行编码，但一个基本问题仍然是如何计算这些信号。该项目要测试的主要假设是，从食物到消费品再到艺术的刺激的价值信号是由大脑通过整合刺激的组成特征或属性以动态方式构建的。虽然许多先前的研究已经使用神经成像技术（例如功能磁共振成像或功能磁共振成像）检查了价值构建，但只能通过该技术的时空分辨率获得见解，而该技术无法测量单个细胞。因此，人们对刺激特征如何由单个细胞表示以及如何整合以计算总体刺激值知之甚少。在这里，可以通过在人类癫痫患者执行三种不同的探索值构建任务时使用颅内记录来克服这一限制。该研究重点关注大脑价值网络三个关键部分的神经元群：杏仁核、外侧眶额叶和腹内侧前额叶皮层。这些方法的空间分辨率使我们能够深入了解各个特征在神经元水平上的表示方式，而时间分辨率使我们能够识别时间动态，通过这些动态集成特征以产生整体价值信号。假设杏仁核和外侧眶额皮质的特征被整合以在腹内侧前额皮质产生价值信号。此外，该研究旨在解决随着总体目标变化而改变价值信号的方式，将特征直接通过上下文变化调节的模型与特征神经元和值编码神经元之间的连接通过目标上下文调节但特征表示保持不变的替代模型进行比较。该项目有望对人脑中价值信号产生的神经计算以及我们个人偏好的起源和神经基础产生基本的机制见解，从而在指导人类决策方面发挥基础作用。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。