Haugg Amelie, Cusack Rhodri, Gonzalez-Lara Laura E, Sorger Bettina, Owen Adrian M, Naci Lorina
Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zurich, Zurich, Switzerland.
Neuroscience Center Zurich, Swiss Federal Institute of Technology, University of Zurich, Zurich, Switzerland.
Front Neurol. 2018 Jun 27;9:492. doi: 10.3389/fneur.2018.00492. eCollection 2018.
It is well established that some patients, who are deemed to have disorders of consciousness, remain entirely behaviorally non-responsive and are diagnosed as being in a vegetative state, yet can nevertheless demonstrate covert awareness of their external environment by modulating their brain activity, a phenomenon known as cognitive-motor dissociation. However, the extent to which these patients retain internal awareness remains unknown. To investigate the potential for internal and external awareness in patients with chronic disorders of consciousness (DoC), we asked whether the pattern of juxtaposition between the functional time-courses of the default mode (DMN) and fronto-parietal networks, shown in healthy individuals to mediate the naturally occurring dominance switching between internal and external aspects of consciousness, was present in these patients. We used a highly engaging movie by Alfred Hitchcock to drive the recruitment of the fronto-parietal networks, including the dorsal attention (DAN) and executive control (ECN) networks, and their maximal juxtaposition to the DMN in response to the complex stimulus, relative to rest and a scrambled, meaningless movie baseline condition. We tested a control group of healthy participants ( = 13/12) and two groups of patients with disorders of consciousness, one comprised of patients who demonstrated independent, neuroimaging-based evidence of covert external awareness ( = 8), and the other of those who did not ( = 8). Similarly to the healthy controls, only the group of patients with overt and, critically, covert external awareness showed significantly heightened differentiation between the DMN and the DAN in response to movie viewing relative to their resting state time-courses, which was driven by the movie's narrative. This result suggested the presence of functional integrity in the DMN and fronto-parietal networks and their relationship to one another in patients with covert external awareness. Similar to the effect in healthy controls, these networks became more strongly juxtaposed to one another in response to movie viewing relative to the baseline conditions, suggesting the for internal and external awareness during complex stimulus processing. Furthermore, our results suggest that naturalistic paradigms can dissociate between groups of DoC patients with and without covert awareness based on the functional integrity of brain networks.
众所周知，一些被认为有意识障碍的患者在行为上完全没有反应，被诊断为处于植物人状态，但他们仍能通过调节大脑活动来表现出对外部环境的隐蔽意识，这种现象被称为认知 - 运动分离。然而，这些患者保留内部意识的程度仍然未知。为了研究慢性意识障碍（DoC）患者的内部和外部意识潜力，我们询问在健康个体中显示出可调节意识的内部和外部方面之间自然发生的优势转换的默认模式（DMN）和额顶叶网络的功能时间进程之间的并列模式，在这些患者中是否存在。我们使用阿尔弗雷德·希区柯克的一部极具吸引力的电影来驱动额顶叶网络的募集，包括背侧注意（DAN）和执行控制（ECN）网络，以及它们相对于休息和一个混乱、无意义的电影基线条件，在对复杂刺激的反应中与DMN的最大并列。我们测试了一组健康参与者（n = 13/12）和两组意识障碍患者，一组由表现出基于神经影像学的独立隐蔽外部意识证据的患者组成（n = 8），另一组则没有（n = 8）。与健康对照组类似，只有具有明显且关键的是隐蔽外部意识的患者组在观看电影时相对于其静息状态时间进程，显示出DMN和DAN之间的显著差异增加，这是由电影叙事驱动的。这一结果表明，在具有隐蔽外部意识的患者中，DMN和额顶叶网络存在功能完整性及其相互关系。与健康对照组的效果类似，相对于基线条件，这些网络在观看电影时彼此之间的并列更加紧密，表明在复杂刺激处理过程中存在内部和外部意识的潜力。此外，我们的结果表明，基于大脑网络的功能完整性，自然主义范式可以区分有无隐蔽意识的DoC患者组。
