对假设和想象的金钱奖励的奖励区域的大胆反应。
BOLD responses in reward regions to hypothetical and imaginary monetary rewards.
机构信息
Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Site, Cambridge, CB23DY, UK.
出版信息
Neuroimage. 2012 Jan 16;59(2):1692-9. doi: 10.1016/j.neuroimage.2011.09.029. Epub 2011 Oct 1.
Monetary rewards are uniquely human. Because money is easy to quantify and present visually, it is the reward of choice for most fMRI studies, even though it cannot be handed over to participants inside the scanner. A typical fMRI study requires hundreds of trials and thus small amounts of monetary rewards per trial (e.g. 5p) if all trials are to be treated equally. However, small payoffs can have detrimental effects on performance due to their limited buying power. Hypothetical monetary rewards can overcome the limitations of smaller monetary rewards but it is less well known whether predictors of hypothetical rewards activate reward regions. In two experiments, visual stimuli were associated with hypothetical monetary rewards. In Experiment 1, we used stimuli predicting either visually presented or imagined hypothetical monetary rewards, together with non-rewarding control pictures. Activations to reward predictive stimuli occurred in reward regions, namely the medial orbitofrontal cortex and midbrain. In Experiment 2, we parametrically varied the amount of visually presented hypothetical monetary reward keeping constant the amount of actually received reward. Graded activation in midbrain was observed to stimuli predicting increasing hypothetical rewards. The results demonstrate the efficacy of using hypothetical monetary rewards in fMRI studies.
金钱奖励是人类独有的。由于金钱很容易量化并以视觉形式呈现,因此它是大多数 fMRI 研究的首选奖励,即使它无法在扫描室内交给参与者。一项典型的 fMRI 研究需要数百次试验,因此如果所有试验都同等对待,每次试验的金钱奖励金额(例如 5 便士)都很小。然而,由于其有限的购买力,小额奖励可能会对表现产生不利影响。假设性的金钱奖励可以克服小额奖励的局限性,但人们对假设性奖励的预测因素是否会激活奖励区域知之甚少。在两项实验中,视觉刺激与假设性金钱奖励相关联。在实验 1 中,我们使用了预测视觉呈现或想象中的假设性金钱奖励的刺激,以及无奖励的对照图片。奖励预测刺激在奖励区域(即内侧眶额皮质和中脑)中产生激活。在实验 2 中,我们参数化地改变了视觉呈现的假设性金钱奖励的数量,同时保持实际收到的奖励数量不变。观察到中脑对预测递增假设性奖励的刺激呈递分级激活。结果表明,在 fMRI 研究中使用假设性金钱奖励是有效的。