Kotchoubey Boris
Institute of Medical Psychology and Behavioural Neurobiology, Eberhardt-Karls-University of Tübingen, Germany.
Neuropsychol Rehabil. 2005 Jul-Sep;15(3-4):333-56. doi: 10.1080/09602010443000416.
Initial conceptualisation about the nature of vegetative state (VS) assumed at least temporary loss of the entire cortical functioning. Since a broad range of stimulus-related cortical activations was demonstrated in VS patients, this simplified idea is not tenable any longer, but no alternative concept emerges instead. Two recent hypotheses, empirically testable and well grounded, could fill this vacuum: (1) In VS, isolated cortical areas may work, but their integration into a distributed network is lacking. (2) In VS, complex stimulus processing is limited to primary sensory and motor areas; the co-ordination between them and the secondary and tertiary areas is lacking. To test these hypotheses, we estimated the frequency of occurrence of late event-related potential components P3 and N400, presumably indicating activity of complex distributed networks including high-level sensory and associative areas. Both components occurred in VS with above-chance frequencies, but less frequently than in two control groups. Besides these frequent normal brain activations, some VS patients exhibit highly significant but abnormal activations, whose functional meaning remains unclear. A methodological analysis leads to the conclusion that any neurophysiological assessment of VS patients is biased toward under-, rather than over-estimation, of their remaining information processing abilities.
关于植物状态（VS）本质的最初概念认为，至少整个皮层功能会暂时丧失。由于在VS患者中已证实存在广泛的与刺激相关的皮层激活，这种简化的观点已不再站得住脚，但取而代之的是没有出现替代概念。最近有两个可通过实证检验且有充分依据的假说，可以填补这一空白：（1）在VS中，孤立的皮层区域可能发挥作用，但它们缺乏整合到分布式网络中的能力。（2）在VS中，复杂的刺激处理仅限于初级感觉和运动区域；它们与次级和三级区域之间缺乏协调。为了检验这些假说，我们估计了晚期事件相关电位成分P3和N400的出现频率，这可能表明包括高级感觉和联合区域在内的复杂分布式网络的活动。这两个成分在VS中出现的频率高于偶然概率，但低于两个对照组。除了这些频繁的正常脑激活外，一些VS患者还表现出高度显著但异常的激活，其功能意义尚不清楚。方法学分析得出的结论是，对VS患者的任何神经生理学评估都倾向于低估而非高估他们剩余的信息处理能力。
