Boorman Erie D, Rajendran Vani G, O'Reilly Jill X, Behrens Tim E
Centre for Functional Magnetic Resonance Imaging of the Brain, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK; Wellcome Trust Centre for Neuroimaging, Institute of Neurology, University College London, 12 Queen Square, London WC1N 3BG, UK; Max Planck UCL Centre for Computational Psychiatry and Ageing Research, Russell Square House, 10-12 Russell Square London WC1B 5EH, UK.
Centre for Functional Magnetic Resonance Imaging of the Brain, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK.
Neuron. 2016 Mar 16;89(6):1343-1354. doi: 10.1016/j.neuron.2016.02.014. Epub 2016 Mar 3.
Complex cognitive processes require sophisticated local processing but also interactions between distant brain regions. It is therefore critical to be able to study distant interactions between local computations and the neural representations they act on. Here we report two anatomically and computationally distinct learning signals in lateral orbitofrontal cortex (lOFC) and the dopaminergic ventral midbrain (VM) that predict trial-by-trial changes to a basic internal model in hippocampus. To measure local computations during learning and their interaction with neural representations, we coupled computational fMRI with trial-by-trial fMRI suppression. We find that suppression in a medial temporal lobe network changes trial-by-trial in proportion to stimulus-outcome associations. During interleaved choice trials, we identify learning signals that relate to outcome type in lOFC and to reward value in VM. These intervening choice feedback signals predicted the subsequent change to hippocampal suppression, suggesting a convergence of signals that update the flexible representation of stimulus-outcome associations.
复杂的认知过程既需要精细的局部处理，也需要不同脑区之间的相互作用。因此，能够研究局部计算与它们所作用的神经表征之间的远距离相互作用至关重要。在这里，我们报告了外侧眶额皮质（lOFC）和多巴胺能腹侧中脑（VM）中两种在解剖学和计算上截然不同的学习信号，它们预测海马体中一个基本内部模型的逐次试验变化。为了测量学习过程中的局部计算及其与神经表征的相互作用，我们将计算功能磁共振成像（fMRI）与逐次试验fMRI抑制相结合。我们发现，内侧颞叶网络中的抑制与刺激-结果关联成比例地逐次试验变化。在交错选择试验中，我们识别出与lOFC中的结果类型以及VM中的奖励价值相关的学习信号。这些中间的选择反馈信号预测了海马体抑制的后续变化，表明信号汇聚以更新刺激-结果关联的灵活表征。
