Department of Neuroscience and Imaging, Gabriele d'Annunzio University, 66013 Chieti, Italy, Institute for Advanced Biomedical Technologies, Gabriele d'Annunzio University Foundation, 66013 Chieti, Italy, and
Department of Neuroscience and Imaging, Gabriele d'Annunzio University, 66013 Chieti, Italy, Institute for Advanced Biomedical Technologies, Gabriele d'Annunzio University Foundation, 66013 Chieti, Italy, and.
J Neurosci. 2014 May 14;34(20):6993-7006. doi: 10.1523/JNEUROSCI.3911-13.2014.
Previous studies on perceptual decision-making have often emphasized a tight link between decisions and motor intentions. Human decisions, however, also depend on memories or experiences that are not closely tied to specific motor responses. Recent neuroimaging findings have suggested that, during episodic retrieval, parietal activity reflects the accumulation of evidence for memory decisions. It is currently unknown, however, whether these evidence accumulation signals are functionally linked to signals for motor intentions coded in frontoparietal regions and whether activity in the putative memory accumulator tracks the amount of evidence for only previous experience, as reflected in "old" reports, or for both old and new decisions, as reflected in the accuracy of memory judgments. Here, human participants used saccadic-eye and hand-pointing movements to report recognition judgments on pictures defined by different degrees of evidence for old or new decisions. A set of cortical regions, including the middle intraparietal sulcus, showed a monotonic variation of the fMRI BOLD signal that scaled with perceived memory strength (older > newer), compatible with an asymmetrical memory accumulator. Another set, including the hippocampus and the angular gyrus, showed a nonmonotonic response profile tracking memory accuracy (higher > lower evidence), compatible with a symmetrical accumulator. In contrast, eye and hand effector-specific regions in frontoparietal cortex tracked motor intentions but were not modulated by the amount of evidence for the effector outcome. We conclude that item recognition decisions are supported by a combination of symmetrical and asymmetrical accumulation signals largely segregated from motor intentions.
先前关于知觉决策的研究通常强调决策与运动意图之间的紧密联系。然而，人类的决策也依赖于与特定运动反应没有紧密联系的记忆或经验。最近的神经影像学研究结果表明，在情景检索期间，顶叶活动反映了记忆决策的证据积累。然而，目前尚不清楚这些证据积累信号是否与编码在前顶叶区域的运动意图信号功能相关，以及活动是否仅跟踪先前经验的证据量（如“旧”报告中所反映的），或者是新旧决策的证据量（如记忆判断的准确性所反映的）。在这里，人类参与者使用扫视眼和手指点运动来报告对不同程度新旧决策证据的图片的识别判断。一组包括中间顶内沟在内的皮质区域表现出 fMRI BOLD 信号的单调变化，其与感知记忆强度（旧的>新的）成比例，与不对称记忆累加器兼容。另一组包括海马体和角回，表现出与记忆准确性相关的非单调反应特征（高>低证据），与对称累加器兼容。相比之下，顶叶皮质中的眼和手效应特定区域跟踪运动意图，但不受效应器结果证据量的调节。我们得出结论，项目识别决策由对称和不对称积累信号的组合支持，这些信号主要与运动意图分离。
