传感神经元能够预测动物即将做出的决定的能力在过去十年里激起人们巨大兴趣，人们关于这些神经元的活动会以某种方式促成正确决策的印象比以前更深了。
在一项涉及在一个基于视频的双眼像差辨别任务中让猴子做出选择的研究中，Hendrikje Nienborg 和 Bruce Cumming发现，这一模型过于简单。他们的数据显示了一个相反方向的因果关系：一旦一个决定被做出，这个决定本身将改变传感神经元的反应。关于要看什么的决定会主动地改变所看到的东西。（生物谷Bioon.com）
生物谷推荐原始出处：
Nature 459, 89-92 (7 May 2009) | doi:10.1038/nature07821
Decision-related activity in sensory neurons reflects more than a neuron's causal effect
Hendrikje Nienborg1 & Bruce G. Cumming1
Laboratory of Sensorimotor Research, National Eye Institute, National Institutes of Health, 49 Convent Drive, Bethesda, Maryland 20892, USA
During perceptual decisions, the activity of sensory neurons correlates with a subject's percept, even when the physical stimulus is identical1, 2, 3, 4, 5, 6, 7, 8, 9. The origin of this correlation is unknown. Current theory proposes a causal effect of noise in sensory neurons on perceptual decisions10, 11, 12, but the correlation could result from different brain states associated with the perceptual choice13 (a top-down explanation). These two schemes have very different implications for the role of sensory neurons in forming decisions14. Here we use white-noise analysis15 to measure tuning functions of V2 neurons associated with choice and simultaneously measure how the variation in the stimulus affects the subjects' (two macaques) perceptual decisions16, 17, 18. In causal models, stronger effects of the stimulus upon decisions, mediated by sensory neurons, are associated with stronger choice-related activity. However, we find that over the time course of the trial these measures change in different directions—at odds with causal models. An analysis of the effect of reward size also supports this conclusion. Finally, we find that choice is associated with changes in neuronal gain that are incompatible with causal models. All three results are readily explained if choice is associated with changes in neuronal gain caused by top-down phenomena that closely resemble attention19. We conclude that top-down processes contribute to choice-related activity. Thus, even forming simple sensory decisions involves complex interactions between cognitive processes and sensory neurons.
