Department of Medicine (Neurology), University of British Columbia, Vancouver, Canada.
Neuroscience. 2011 Nov 24;196:168-77. doi: 10.1016/j.neuroscience.2011.08.006. Epub 2011 Aug 6.
Monkey studies report greater activity in the lateral intraparietal area and more efficient saccades when targets coincide with the location of prior reward cues, even when cue location does not indicate which responses will be rewarded. This suggests that reward can modulate spatial attention and visual selection independent of the "action value" of the motor response. Our goal was first to determine whether reward modulated visual selection similarly in humans, and next, to discover whether reward and penalty differed in effect, if cue effects were greater for cognitively demanding antisaccades, and if financial consequences that were contingent on stimulus location had spatially selective effects. We found that motivational cues reduced all latencies, more for reward than penalty. There was an "inhibition-of-return"-like effect at the location of the cue, but unlike the results in monkeys, cue valence did not modify this effect in prosaccades, and the inhibition-of-return effect was slightly increased rather than decreased in antisaccades. When financial consequences were contingent on target location, locations without reward or penalty consequences lost the benefits seen in noncontingent trials, whereas locations with consequences maintained their gains. We conclude that unlike monkeys, humans show reward effects not on visual selection but on the value of actions. The human saccadic system has both the capacity to enhance responses to multiple locations simultaneously, and the flexibility to focus motivational enhancement only on locations with financial consequences. Reward is more effective than penalty, and both interact with the additional attentional demands of the antisaccade task.
猴子研究报告表明，当目标与先前奖励线索的位置重合时，外侧顶内区的活动增加，眼跳更有效，即使线索位置不能指示哪些反应将得到奖励。这表明，奖励可以调节空间注意力和视觉选择，而不依赖于运动反应的“动作价值”。我们的目标首先是确定奖励是否以类似的方式调节人类的视觉选择，其次是发现奖励和惩罚是否有不同的效果，如果线索效应在认知要求较高的反眼跳中更大，以及如果刺激位置相关的财务后果是否具有空间选择性效应。我们发现，动机线索减少了所有的潜伏期，奖励的潜伏期比惩罚的潜伏期更短。在线索的位置存在类似于“返回抑制”的效应，但与猴子的结果不同，线索效价并没有改变这种效应在正眼跳中的作用，而在反眼跳中，返回抑制效应略有增加而不是减少。当财务后果与目标位置相关时，没有奖励或惩罚后果的位置失去了在非相关试验中看到的好处，而有后果的位置则保持了收益。我们的结论是，与猴子不同，人类表现出的奖励效应不是在视觉选择上，而是在动作的价值上。人类的扫视系统既有同时增强对多个位置反应的能力，也有只将动机增强集中在有财务后果的位置的灵活性。奖励比惩罚更有效，两者都与反眼跳任务的额外注意力需求相互作用。
