Walsh Eamonn, Oakley David A, Halligan Peter W, Mehta Mitul A, Deeley Quinton
Cultural and Social Neuroscience Group, Institute of Psychiatry, Psychology, and Neuroscience, King's College London, UK.
Department of Psychological Sciences, Birkbeck, University of London, UK.
Soc Cogn Affect Neurosci. 2017 May 1;12(5):793-801. doi: 10.1093/scan/nsw185.
Loss or reduction of awareness is common in neuropsychiatric disorders and culturally influenced dissociative phenomena but the underlying brain mechanisms are poorly understood. fMRI was combined with suggestions for automatic writing in 18 healthy highly hypnotically suggestible individuals in a within-subjects design to determine whether clinical alterations in awareness of thought and movement can be experimentally modelled and studied independently of illness. Subjective ratings of control, ownership, and awareness of thought and movement, and fMRI data were collected following suggestions for thought insertion and alien control of writing movement, with and without loss of awareness. Subjective ratings confirmed that suggestions were effective. At the neural level, our main findings indicated that loss of awareness for both thought and movement during automatic writing was associated with reduced activation in a predominantly left-sided posterior cortical network including BA 7 (superior parietal lobule and precuneus), and posterior cingulate cortex, involved in self-related processing and awareness of the body in space. Reduced activity in posterior parietal cortices may underlie specific clinical and cultural alterations in awareness of thought and movement. Clinically, these findings may assist development of imaging assessments for loss of awareness of psychological origin, and interventions such as neurofeedback.
意识丧失或减退在神经精神疾病以及受文化影响的分离性现象中很常见，但其中潜在的大脑机制却鲜为人知。在一项被试内设计中，功能性磁共振成像（fMRI）与针对18名健康的、高度易被催眠的个体进行自动书写的建议相结合，以确定思维和运动意识的临床改变是否可以在不依赖疾病的情况下通过实验进行模拟和研究。在有或没有意识丧失的情况下，根据思维插入和书写运动的异己控制建议，收集了对控制、所有权以及思维和运动意识的主观评分以及fMRI数据。主观评分证实了这些建议是有效的。在神经层面，我们的主要发现表明，自动书写过程中思维和运动意识的丧失与一个主要位于左侧的后皮质网络的激活减少有关，该网络包括BA 7（顶上小叶和楔前叶）以及后扣带回皮质，参与自我相关加工和对空间中身体的意识。顶叶后部皮质的活动减少可能是思维和运动意识的特定临床和文化改变的基础。在临床上，这些发现可能有助于开发针对心理源性意识丧失的影像学评估方法以及诸如神经反馈等干预措施。
