The role of cingulate cortex in reward-based decision making

描述（由申请人提供）：成瘾可能是由决策和奖励处理紊乱引起的。因此，了解奖励引导决策的神经机制有可能帮助那些吸毒成瘾者。一个特殊的大脑区域，后扣带皮层（CGp），与各种与成瘾相关的决策过程有关，包括那些涉及风险、时间和社会信息的选择。最近的研究表明，CGp中的神经元反应可能在对风险和时间做出决定时对所选择选项的主观价值进行编码。因此，CGp函数的一个中心假设是，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共同的价值度量中。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环境(例如……（风险或延迟），但真正的主观价值表征应该独立于上下文。关于CGp功能的另一个谜团是它与前扣带皮层（ACC）的关系，特别是在涉及延迟、风险和社会信息的决策中。比较可能会揭示这两个区域的作用，以及基于奖励的决策机制，因为两者之间存在很强的相互联系。我提出了三个独立的实验来解决这些文献中的空白。我将记录CGp和ACC中单个神经元在涉及与成瘾相关的三种不同决策环境的任务中的反应：风险、延迟折扣和社会强化。我假设，CGp神经元的激活率将独立于决策环境发出主观价值信号，并且在涉及社会强化的决策中，ACC神经元的反应调节将比CGp神经元的反应调节更大，而CGp神经元对涉及风险的决策的反应调节相对更大。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来在决策中发挥因果作用。成瘾可以被定义为决策问题，即无法对风险、回报和延迟满足做出正确的决定。了解大脑是如何做出决定的，在试图理解和解决药物成瘾或滥用造成的复杂健康问题方面具有巨大的作用。我建议研究一个特别神秘的大脑区域——扣带皮层是如何指导我们处理奖励和做出决定的，这可能会推动我们解决成瘾问题的进程。

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.