Social reward motivation increases working memory capacity

为了探讨视觉工作记忆（VWM）与奖赏系统之间的动态关系，我们在一个金钱激励延迟反应任务中观察了脑电（EEG）节律。要求14名受试者在保持间隔期间保持几个彩色圆盘（3或6个）。在正确答案的情况下，他们获得了在每次试验开始时提供的价值（0，10或50日元）的金钱奖励。行为学结果表明，高奖赏条件下的VWM容量显著高于低奖赏或无奖赏条件下的VWM容量。EEG结果表明，额叶θ波（6Hz）和顶叶α波（12Hz）的振幅与VWM的维持有关，因为在保持间期内，它们的活动增加，并与VWM的容量相关。额叶β延迟期振幅（24 Hz）与从高奖赏到无奖赏条件下VWM容量的增加显著相关。有趣的是，只有在高奖励条件下，用于奖励动机的额叶β活动和用于VWM存储的顶叶α活动才显着相关。这些结果表明，额顶系统在β和α频域的动态联系可能涉及高奖赏条件下VWM容量的增加。

To investigate the dynamic relationships between the visual working memory (VWM) and reward systems, we focused on the electroencephalograph (EEG) rhythms during a monetary incentive delayed-response task. 14 subjects were required to maintain several colored disks (3 or 6) during the retention interval. In case of the correct answer, they got the monetary reward which value (0, 10 or 50 Japanese yen) was presented at the beginning of each trial. Behavioral results showed that the VWM capacity for the high-reward condition was significantly increased as compared with the low- or no-reward conditions. EEG results showed that the frontal theta (6Hz) and the parietal alpha (12Hz) amplitudes are involved in the maintenance of the VWM since the activities increased during the retention interval and were correlated with the VWM capacity. The frontal beta delay-period amplitudes (24Hz) were significantly correlated with the increases of the VWM capacity from the high-reward to no-reward conditions. Interestingly, the frontal beta activity for reward motivation and the parietal alpha activity for VWM storage were significantly correlated under only the high-reward conditions. These findings suggest that the frontal-parietal system dynamically linked in beta and alpha frequency domains may implicate the increasing VWM capacity under high reward condition.