Hong L Elliot, Summerfelt Ann, McMahon Robert, Adami Helene, Francis Grace, Elliott Amie, Buchanan Robert W, Thaker Gunvant K
Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, P.O. Box 21247, Baltimore, MD 21228, USA.
Schizophr Res. 2004 Oct 1;70(2-3):293-302. doi: 10.1016/j.schres.2003.12.011.
Electroencephalographic (EEG) synchronization in the gamma band is thought to represent a neuronal mechanism by which the brain integrates information processed in different cortical areas to build a coherent internal representation. Previous studies have reported abnormal gamma range ( approximately 40 Hz) synchronization in schizophrenic patients. We tested a group of first-degree relatives of schizophrenic probands who have schizophrenia spectrum personality symptoms, and a group of schizophrenic patients, to examine whether individuals with increased liability for schizophrenia have reduced gamma synchronization.
A steady-state auditory evoked potential paradigm was used to evaluate the brain's capacity to sustain 20, 30, and 40 Hz EEG synchronization in 11 relatives, 24 schizophrenic patients (11 on conventional, 13 on new generation antipsychotic medications), and 17 normal controls.
Relatives with schizophrenic spectrum personality symptoms had reduced power at 40 Hz synchronization compared to normal controls (p=0.022). Previous findings of reduced steady-state gamma band synchronization in schizophrenic patients were not directly replicated in this study. Patients as a group did not significantly differ from controls, but patients taking new generation antipsychotics had significantly enhanced 40 Hz synchronization compared to patients taking conventional antipsychotics (p<0.001). There were no group differences in 20 or 30 Hz synchronization.
Gamma band synchronization was found to be reduced in first-degree relatives with schizophrenia spectrum personality symptoms. Patients on new generation antipsychotic medications may exhibit enhanced gamma band synchronization.
γ频段的脑电图（EEG）同步被认为代表一种神经元机制，通过该机制大脑整合在不同皮质区域处理的信息以构建连贯的内部表征。先前的研究报告了精神分裂症患者存在异常的γ频段（约40赫兹）同步。我们测试了一组有精神分裂症谱系人格症状的精神分裂症先证者的一级亲属以及一组精神分裂症患者，以检查精神分裂症易感性增加的个体是否γ同步降低。
采用稳态听觉诱发电位范式评估11名亲属、24名精神分裂症患者（11名服用传统抗精神病药物，13名服用新一代抗精神病药物）和17名正常对照者维持20、30和40赫兹EEG同步的大脑能力。
与正常对照相比，有精神分裂症谱系人格症状的亲属在40赫兹同步时功率降低（p = 0.022）。本研究未直接重复先前关于精神分裂症患者稳态γ频段同步降低的发现。作为一个整体，患者与对照无显著差异，但与服用传统抗精神病药物的患者相比，服用新一代抗精神病药物的患者40赫兹同步显著增强（p < 0.001）。在20或30赫兹同步方面无组间差异。
发现有精神分裂症谱系人格症状的一级亲属γ频段同步降低。服用新一代抗精神病药物的患者可能表现出增强的γ频段同步。
