Department of Psychology, University of Toronto, ON M5S 3G3, Canada.
Soc Cogn Affect Neurosci. 2007 Dec;2(4):313-22. doi: 10.1093/scan/nsm030.
It has long been theorised that there are two temporally distinct forms of self-reference: extended self-reference linking experiences across time, and momentary self-reference centred on the present. To characterise these two aspects of awareness, we used functional magnetic resonance imaging (fMRI) to examine monitoring of enduring traits ('narrative' focus, NF) or momentary experience ('experiential' focus, EF) in both novice participants and those having attended an 8 week course in mindfulness meditation, a program that trains individuals to develop focused attention on the present. In novices, EF yielded focal reductions in self-referential cortical midline regions (medial prefrontal cortex, mPFC) associated with NF. In trained participants, EF resulted in more marked and pervasive reductions in the mPFC, and increased engagement of a right lateralised network, comprising the lateral PFC and viscerosomatic areas such as the insula, secondary somatosensory cortex and inferior parietal lobule. Functional connectivity analyses further demonstrated a strong coupling between the right insula and the mPFC in novices that was uncoupled in the mindfulness group. These results suggest a fundamental neural dissociation between two distinct forms of self-awareness that are habitually integrated but can be dissociated through attentional training: the self across time and in the present moment.
长期以来,人们一直认为自我参照有两种时间上明显不同的形式:延伸的自我参照将经验联系起来跨越时间,而瞬间的自我参照则以现在为中心。为了描述这两种意识方面,我们使用功能磁共振成像(fMRI)来检查新手参与者和参加了 8 周正念冥想课程的参与者对持久特征(“叙述性”焦点,NF)或瞬间体验(“体验性”焦点,EF)的监测。在新手参与者中,EF 导致与 NF 相关的自我参照皮质中线区域(内侧前额叶皮层,mPFC)的焦点减少。在训练有素的参与者中,EF 导致 mPFC 更明显和普遍的减少,并增加了右侧偏侧化网络的参与,包括外侧前额叶皮层和内脏躯体区域,如岛叶、次级体感皮层和下顶叶叶。功能连接分析进一步表明,在新手参与者中,右岛叶和 mPFC 之间存在很强的耦合,而在正念组中则没有耦合。这些结果表明,两种不同形式的自我意识之间存在着一种基本的神经分离,它们通常是整合的,但可以通过注意力训练来分离:过去和现在的自我。