Sheffield Cognition and Neuroimaging Laboratory (SCANLab), Academic Clinical Psychiatry, Department of Neuroscience, Faculty of Medicine, Dentistry and Health, Sheffield S5 7JT, UK.
Neuroimage. 2010 Nov 1;53(2):611-8. doi: 10.1016/j.neuroimage.2010.06.053. Epub 2010 Jun 30.
In this study, we investigated brain mechanisms for the generation of subjective experience from objective sensory inputs. Our experimental construct was subjective tranquility. Tranquility is a mental state more likely to occur in the presence of objective sensory inputs that arise from natural features in the environment. We used functional magnetic resonance imaging to examine the neural response to scenes that were visually distinct (beach images vs. freeway images) and experienced as tranquil (beach) or non-tranquil (freeway). Both sets of scenes had the same auditory component because waves breaking on a beach and vehicles moving on a freeway can produce similar auditory spectral and temporal characteristics, perceived as a constant roar. Compared with scenes experienced as non-tranquil, we found that subjectively tranquil scenes were associated with significantly greater effective connectivity between the auditory cortex and medial prefrontal cortex, a region implicated in the evaluation of mental states. Similarly enhanced connectivity was also observed between the auditory cortex and posterior cingulate gyrus, temporoparietal cortex and thalamus. These findings demonstrate that visual context can modulate connectivity of the auditory cortex with regions implicated in the generation of subjective states. Importantly, this effect arises under conditions of identical auditory input. Hence, the same sound may be associated with different percepts reflecting varying connectivity between the auditory cortex and other brain regions. This suggests that subjective experience is more closely linked to the connectivity state of the auditory cortex than to its basic sensory inputs.
在这项研究中，我们调查了从客观感觉输入产生主观体验的大脑机制。我们的实验构想是主观宁静。宁静是一种更有可能在客观感觉输入存在的情况下出现的心理状态，这些输入来自环境中的自然特征。我们使用功能磁共振成像来检查对视觉上不同的场景（海滩图像与高速公路图像）和被体验为宁静（海滩）或不宁静（高速公路）的神经反应。这两组场景都有相同的听觉成分，因为在海滩上破裂的海浪和在高速公路上行驶的车辆可以产生相似的听觉频谱和时间特征，被感知为持续的轰鸣声。与被体验为不宁静的场景相比，我们发现主观上宁静的场景与听觉皮层和内侧前额叶皮层之间的有效连接显著增加，内侧前额叶皮层是参与评估心理状态的区域。在听觉皮层和后扣带回、颞顶叶皮层和丘脑之间也观察到类似的增强连接。这些发现表明，视觉背景可以调节听觉皮层与产生主观状态相关的区域之间的连接。重要的是，这种效应是在相同听觉输入的条件下产生的。因此，相同的声音可能与不同的感知相关联，反映了听觉皮层与其他大脑区域之间的连接变化。这表明主观体验与听觉皮层的连接状态比其基本感觉输入更密切相关。
