The role of cingulate cortex in reward-based decision making

描述(由申请者提供)：上瘾可能是由于决策和奖励过程的混乱造成的。因此，了解奖赏导向决策的神经机制有可能帮助那些滥用药物上瘾的人。一个特殊的大脑区域，后扣带回皮质(CGP)，参与了与成瘾相关的各种决策过程，包括涉及风险、时间和社会信息的选择。最近的研究表明，在关于风险和时间的决策过程中，CGP的神经元反应可能编码了所选选项的主观价值。因此，CGP功能的一个中心假设是，它是一个专门系统的一部分，该系统将来自多个来源的信息集成到一个单一的公共价值度量中。然而，这些早期研究的一个主要局限性是，它们只关注单一的决策背景(例如，风险或延迟)，但真正的主观价值表征应该独立于背景。关于CGP功能的另一个谜团涉及到它与前扣带回(ACC)的关系，特别是在涉及延迟、风险和社会信息的决策中。比较可能有助于了解这两个地区的作用，以及总体上基于奖励的决策机制，因为两者之间存在很强的互惠联系。我提议用三个不同的实验来填补文献中的这些空白。我将记录CGP和ACC中单个神经元在一项任务中的反应，该任务涉及三种与成瘾相关的不同决策情境：风险、延迟折扣和社会强化。我假设CGP神经元的放电频率将发出与决策环境无关的主观价值信号，在涉及社会强化的决策中，ACC神经元的反应调制将大于CGP神经元，而CGP神经元对涉及风险的决策将有相对较大的调制。最后，我将测试在CGP中观察到的放电模式是否通过可逆地使该区域失活而在决策中发挥因果作用。上瘾可以被认为是一个决策问题，无法在风险、回报和延迟满足方面做出正确的决定。了解大脑是如何做出决定的，在试图理解和解决滥用药物成瘾这一复杂的健康问题时可以发挥巨大的作用。我提议研究一个特别神秘的大脑区域--扣带回皮质--如何引导我们处理奖励和做出决定，这可能会推动我们在解决成瘾问题上取得进展。

DESCRIPTION (provided by applicant): Addiction may be caused by disordered decision making and reward processing. Thus, understanding the neural mechanisms of reward-guided decision making has the potential to help those addicted to drugs of abuse. One particular brain region, posterior cingulate cortex (CGp), has been implicated in a variety of decision making processes relevant to addiction, including those choices involving risk, time, and social information. Recent studies have suggested that neuronal responses in CGp may encode the subjective value of a chosen option during decisions about risk and time. Thus, a central hypothesis of CGp function is that it is part of a specialized system that integrates information from multiple sources into a single common metric of value. However, one major limitation of these earlier studies is that they have focused on a single decision context (e.g.., risk or delay), but true subjective value representations should be independent of context. Another mystery about CGp function concerns its relationship with the anterior cingulate cortex (ACC), particularly in those decisions involving delays, risk, and social information. A comparison could potentially shed light on the roles of both regions, as well as the mechanisms of reward-based decision making in general, as there are strong reciprocal connections between the two. I am proposing three separate experiments to address these gaps in the literature. I will record responses of single neurons in CGp and ACC during a task involving three different decision contexts relevant to addiction: risk, delay discounting, and social reinforcement. I hypothesize that firing rates of CGp neurons will signal subjective value independent of decision context, and that response modulations of ACC neurons will be greater than those of CGp neurons during decisions involving social reinforcement, whereas CGp neurons will have relatively larger modulations to decisions involving risk. Finally, I will test whether firing patterns observed in CGp play a causal role in decision making by reversibly inactivating this region. Addiction can be framed as a problem of decision making, of failing to make good decisions about risks, rewards, and delaying gratification. Knowing how the brain makes decisions can be of enormous use in trying to understand and solve the complex health problem of addiction to drugs of abuse. I propose to study how a particularly mysterious brain region known as cingulate cortex guides how we process rewards and make decisions, which may advance our progress toward solving the problem of addiction.