Medial prefrontal cortex and self-referential mental activity: Relation to a default mode of brain function
Medial prefrontal cortex and self-referential mental activity: Relation to a default mode of brain function
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DOI：
10.1073/pnas.071043098
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发表时间：
2001-03-27
影响因子：
11.1
通讯作者：
Raichle, ME
中科院分区：
文献类型：
--
作者：
Gusnard, DA;Akbudak, E;Raichle, ME
内侧前额叶皮层（MPFC）是在休息时具有最高基线代谢活动的大脑区域之一，并且在功能成像研究中，在各种目标导向行为中表现出从该基线降低的代谢活动。这种高代谢率和这种行为表明存在一种有组织的默认脑功能模式，其中的元素可能被削弱或增强。现有的数据表明，这些MPFC区域可能有助于多方面“自我”的神经实例化。“我们通过定位和操纵MPFC默认状态活动的元素来探索这一重要概念。在这项功能性磁共振成像（fMRI）研究中，受试者做出两种判断，一种是自我参照，另一种不是对情感规范的图片做出反应：愉快与不愉快（内部线索条件，ICC）和室内与室外（外部线索条件，ECC）。ICC优先与背侧MPFC的活动增加沿着。这些增加都伴随着腹侧MPFC的主动任务条件的减少。这些结果支持的观点，背侧和腹侧MPFC的差异影响注意要求的任务和明确的自我参照任务。自我参照心理活动的存在似乎与背侧MPFC从基线的增加有关，背侧MPFC的减少与需要注意力的任务减弱情绪处理的事实一致。我们认为，自我指涉的心理活动和情绪处理的默认状态的元素所代表的MPFC活动。我们认为，探索自我的神经生物学的一个有用的方法是探索默认状态活动的性质。
Medial prefrontal cortex (MPFC) is among those brain regions having the highest baseline metabolic activity at rest and one that exhibits decreases from this baseline across a wide variety of goal-directed behaviors in functional imaging studies. This high metabolic rate and this behavior suggest the existence of an organized mode of default brain function, elements of which may be either attenuated or enhanced. Extant data suggest that these MPFC regions may contribute to the neural instantiation of aspects of the multifaceted "self." We explore this important concept by targeting and manipulating elements of MPFC default state activity. In this functional magnetic resonance imaging (fMRI) study, subjects made two judgments, one self-referential, the other not in response to affectively normed pictures: pleasant vs, unpleasant (an internally cued condition, ICC) and indoors vs. outdoors (an externally cued condition, ECC), The ICC was preferentially associated with activity increases along the dorsal MPFC. These increases were accompanied by decreases in both active task conditions in ventral MPFC. These results support the view that dorsal and ventral MPFC are differentially influenced by attention-demanding tasks and explicitly self-referential tasks. The presence of self-referential mental activity appears to be associated with increases from the baseline in dorsal MPFC, Reductions in Ventral MPFC occurred consistent with the fact that attention-demanding tasks attenuate emotional processing. We posit that both self-referential mental activity and emotional processing represent elements of the default state as represented by activity in MPFC. We suggest that a useful way to explore the neurobiology of the self is to explore the nature of default state activity.