Faculty of Psychology, Technische Universität Dresden, Dresden, Germany.
Department of Psychiatry & Psychotherapy, University of Tübingen, Tübingen, Germany; Department of Psychiatry and Neuroimaging Center, Technische Universität Dresden, Dresden, Germany.
Neuropsychologia. 2020 Dec;149:107675. doi: 10.1016/j.neuropsychologia.2020.107675. Epub 2020 Nov 11.
Perceptual decisions entail the accumulation of evidence until a decision criterion is reached. The amount of noise in this process is inversely related to the behavioral performance of the decision-maker. Hence, reducing the amount of perceived noise could improve performance in perceptual decisions. In this study, we investigated whether providing monetary reward for correct responses in a perceptual decision-making task would enhance performance based on prior research linking noise reduction to the administration of reward. To this end, thirty-one healthy young adults carried out an incentivized dot tracking task (iDT) during recording of functional magnetic resonance imaging (fMRI). Behavioral responses were fitted to a Bayesian version of the drift-diffusion model that, among other parameters, also includes an estimate of sensory noise. Fifty percent of the trials were incentivized to compare rewarded with unrewarded trials regarding behavior, brain responses and estimates of model parameters. In order to establish a link between the noise parameter and fMRI activity, we correlated percent signal change (PSC) values from nucleus accumbens and caudate nucleus with noise levels in rewarded and unrewarded trials respectively. Although reward did not affect behavioral performance and model parameters, the fMRI analyses showed notable differences in nucleus accumbens, caudate nucleus and rostral anterior cingulate cortex in rewarded relative to unrewarded trials. Furthermore, higher PSC within nucleus accumbens was significantly associated with lower sensory noise levels, which was specific to rewarded trials. This work is consistent with previous findings on reward modulation of brain responses and marks a first step towards elucidating the effects of reward-induced noise suppression during perceptual decision-making.
知觉决策需要积累证据，直到达到决策标准。这个过程中的噪声量与决策者的行为表现成反比。因此，减少感知噪声的量可以提高知觉决策的性能。在这项研究中，我们调查了在知觉决策任务中为正确反应提供金钱奖励是否会根据先前的研究提高性能，该研究将减少噪声与奖励的实施联系起来。为此，三十一名健康的年轻人在进行功能磁共振成像 (fMRI) 记录的同时进行了激励点跟踪任务 (iDT)。行为反应符合贝叶斯漂移扩散模型的版本，该模型除了其他参数外，还包括对感官噪声的估计。百分之五十的试验被激励为奖励试验和非奖励试验进行比较，以比较行为、大脑反应和模型参数的估计。为了建立噪声参数与 fMRI 活动之间的联系，我们分别将伏隔核和尾状核的信号变化百分比 (PSC) 值与奖励和非奖励试验中的噪声水平相关联。尽管奖励并没有影响行为表现和模型参数，但 fMRI 分析显示，在奖励试验中，伏隔核、尾状核和额前扣带皮层有明显的差异。此外，伏隔核内较高的 PSC 值与较低的感觉噪声水平显著相关，这是奖励试验特有的。这项工作与先前关于奖励对大脑反应的调节的发现一致，并标志着阐明奖励诱导的知觉决策过程中噪声抑制的影响的第一步。
