Rosburg Timm, Trautner Peter, Fell Jürgen, Moxon Karen Anne, Elger Christian E, Boutros Nash N
Department of Epileptology, University of Bonn, Bonn, Germany.
Neuroimage. 2009 Feb 1;44(3):1041-9. doi: 10.1016/j.neuroimage.2008.09.035. Epub 2008 Oct 10.
For patients with schizophrenia, a deficient gating (or filtering) of sensory input has been described. One major approach to study this sensory gating is to measure event-related potentials (ERPs) in response to paired clicks. In these experiments, sensory gating is quantified as amplitude reduction of the ERP components P50 and N100 from the 1st to the 2nd stimulus. In ERP studies brain electrical signals are averaged over single trials. Alterations in phase locking might be one factor contributing to the observed deficits in sensory gating, but findings have been inconclusive as yet. In particular, the contribution of different frequency bands to the deficit required further investigation. We studied N100 gating by intracranial recordings in a sample of epilepsy patients and subdivided the group into good and poor gators of the intracranial ERP component N100. Data were evaluated by frequency specific wavelet-based phase and power analyses. Poor N100 gators had an increased phase locking in the frequency range from 6.0-15.1 Hz after the 2nd stimulus, as compared to good gators. Other group differences were apparent already before the 2nd stimulus. Poor gators had less phase locked beta band activity (20.2-30.0 Hz) than good gators 200-315 ms after the onset of the 1st stimulus. Within the group of poor gators, lower values of phase locking in this frequency range were also associated with lower gating ratios. The reduced beta band response in response to the 1st stimulus may reflect poorer memory encoding of the 1st stimulus in poor gators. This in turn might lead to increased demands to process the 2nd stimulus.
对于精神分裂症患者，已有研究描述其感觉输入的门控（或过滤）功能存在缺陷。研究这种感觉门控的一种主要方法是测量对配对点击声的事件相关电位（ERP）。在这些实验中，感觉门控被量化为ERP成分P50和N100从第一个刺激到第二个刺激的振幅降低。在ERP研究中，脑电信号是在单次试验上进行平均的。锁相的改变可能是导致观察到的感觉门控缺陷的一个因素，但目前的研究结果尚无定论。特别是，不同频段对该缺陷的贡献需要进一步研究。我们通过对癫痫患者样本进行颅内记录来研究N100门控，并将该组患者分为颅内ERP成分N100的良好门控者和较差门控者。通过基于频率特异性小波的相位和功率分析对数据进行评估。与良好门控者相比，较差的N100门控者在第二个刺激后6.0 - 15.1 Hz频率范围内的锁相增加。在第二个刺激之前，其他组间差异就已明显。较差门控者在第一个刺激开始后200 - 315毫秒时，其β频段（20.2 - 30.0 Hz）的锁相活动比良好门控者少。在较差门控者组内，该频率范围内较低的锁相值也与较低的门控比率相关。对第一个刺激的β频段反应降低可能反映了较差门控者对第一个刺激的记忆编码较差。这反过来可能导致处理第二个刺激的需求增加。
