Wellcome Trust Centre for Neuroimaging, Institute of Neurology, University College London, London WC1N 3BG, United Kingdom.
J Neurosci. 2013 Feb 13;33(7):3202-11. doi: 10.1523/JNEUROSCI.2532-12.2013.
A dominant focus in studies of learning and decision-making is the neural coding of scalar reward value. This emphasis ignores the fact that choices are strongly shaped by a rich representation of potential rewards. Here, using fMRI adaptation, we demonstrate that responses in the human orbitofrontal cortex (OFC) encode a representation of the specific type of food reward predicted by a visual cue. By controlling for value across rewards and by linking each reward with two distinct stimuli, we could test for representations of reward-identity that were independent of associative information. Our results show reward-identity representations in a medial-caudal region of OFC, independent of the associated predictive stimulus. This contrasts with a more rostro-lateral OFC region encoding reward-identity representations tied to the predicate stimulus. This demonstration of adaptation in OFC to reward specific representations opens an avenue for investigation of more complex decision mechanisms that are not immediately accessible in standard analyses, which focus on correlates of average activity.
学习和决策研究的一个主要焦点是标量奖励价值的神经编码。这种强调忽略了一个事实，即选择受到潜在奖励的丰富表示强烈影响。在这里，我们使用 fMRI 适应来证明人类眶额皮层（OFC）的反应编码了视觉提示预测的特定类型食物奖励的表示。通过控制奖励之间的价值，并将每个奖励与两个不同的刺激联系起来，我们可以测试与联想信息无关的奖励身份的表示。我们的结果显示，OFC 中一个中后部区域存在与奖励相关的身份表示，与相关的预测刺激无关。这与编码与谓语刺激相关的奖励身份表示的更额侧 OFC 区域形成对比。OFC 中对奖励特定表示的适应的这种证明为研究更复杂的决策机制开辟了途径，这些机制在标准分析中无法直接获得，而标准分析侧重于平均活动的相关性。
