Apps Matthew A J, Ramnani Narender
Department of Psychology, Royal Holloway, University of London, Egham TW20 0EX, United Kingdom, Nuffield Department of Clinical Neuroscience, University of Oxford, John Radcliffe Hospital, Oxford OC3 9DU, United Kingdom and Department of Experimental Psychology, University of Oxford, Oxford OX1 3UD, United Kingdom.
J Neurosci. 2014 Apr 30;34(18):6190-200. doi: 10.1523/JNEUROSCI.2701-13.2014.
Evaluating the costs and benefits of our own choices is central to most forms of decision-making and its mechanisms in the brain are becoming increasingly well understood. To interact successfully in social environments, it is also essential to monitor the rewards that others receive. Previous studies in nonhuman primates have found neurons in the anterior cingulate cortex (ACC) that signal the net value (benefit minus cost) of rewards that will be received oneself and also neurons that signal when a reward will be received by someone else. However, little is understood about the way in which the human brain engages in cost-benefit analyses during social interactions. Does the ACC signal the net value (the benefits minus the costs) of rewards that others will receive? Here, using fMRI, we examined activity time locked to cues that signaled the anticipated reward magnitude (benefit) to be gained and the level of effort (cost) to be incurred either by a subject themselves or by a social confederate. We investigated whether activity in the ACC covaries with the net value of rewards that someone else will receive when that person is required to exert effort for the reward. We show that, although activation in the sulcus of the ACC signaled the costs on all trials, gyral ACC (ACC(g)) activity varied parametrically only with the net value of rewards gained by others. These results suggest that the ACC(g) plays an important role in signaling cost-benefit information by signaling the value of others' rewards during social interactions.
评估我们自身选择的成本和收益是大多数决策形式的核心，其在大脑中的机制也越来越为人所理解。要在社交环境中成功互动，监测他人获得的奖励也至关重要。此前对非人类灵长类动物的研究发现，前扣带回皮质（ACC）中的神经元会发出自身将获得奖励的净值（收益减去成本）信号，也有神经元会在他人将获得奖励时发出信号。然而，对于人类大脑在社交互动过程中进行成本效益分析的方式，我们了解甚少。ACC是否会发出他人将获得奖励的净值（收益减去成本）信号呢？在这里，我们使用功能磁共振成像（fMRI），研究了与提示信号锁定的活动时间，这些提示信号表明了受试者自身或社交伙伴预期获得的奖励大小（收益）以及需要付出的努力程度（成本）。我们调查了在要求他人为奖励付出努力时，ACC的活动是否与他人将获得奖励的净值相关。我们发现，尽管ACC沟回的激活在所有试验中都表明了成本，但脑回ACC（ACC(g)）的活动仅随他人获得奖励的净值呈参数性变化。这些结果表明，ACC(g)在社交互动过程中通过发出他人奖励的价值信号，在发出成本效益信息方面发挥着重要作用。
