Jin Y, Potkin S G, Patterson J V, Sandman C A, Hetrick W P, Bunney W E
Department of Psychiatry and Human Behavior, University of California Irvine Medical Center, Orange 92668, USA.
Psychiatry Res. 1997 May 5;70(2):71-81. doi: 10.1016/s0165-1781(97)03091-6.
The conditioning-testing (S1-S2) P50 auditory evoked potential (EP) has been well-documented and accepted as an important tool for measuring sensory gating in schizophrenia research. However, the physiological mechanism of the phenomenon is not known. In this study a single-trial analysis was used to determine the influence of the latency variability of the responses in the formation of the averaged P50. Ten schizophrenic patients and 10 normal controls were tested in the dual-click EP paradigm. Using ensemble averaging analysis, we replicated the previous finding of a lower S1 P50 amplitude and higher S2/S1 ratio in schizophrenics compared with normal controls. The single-trial analysis revealed that patients had significantly higher trial-to-trial latency variability in S1 responses than normal subjects, while the S2 showed the same variability as in controls. Measured by the single-trial procedure, the arithmetic mean amplitudes of P50 responses to S1 and S2 were similar between normal and schizophrenic subjects. The same measure also eliminated the difference in averaged P50 amplitude between S1 and S2 for both groups. Temporal variability appears to be an important factor in the assessment of averaged EPs and thus contribute to the change of P50 amplitude observed in schizophrenia.
条件刺激-测试（S1-S2）P50听觉诱发电位（EP）已有充分记录，并被公认为精神分裂症研究中测量感觉门控的重要工具。然而，该现象的生理机制尚不清楚。在本研究中，采用单试次分析来确定反应潜伏期变异性在平均P50形成过程中的影响。对10例精神分裂症患者和10名正常对照者进行了双击EP范式测试。使用总体平均分析，我们重复了之前的发现，即与正常对照相比，精神分裂症患者的S1 P50波幅较低，S2/S1比值较高。单试次分析显示，患者S1反应的试次间潜伏期变异性显著高于正常受试者，而S2的变异性与对照组相同。通过单试次程序测量，正常受试者和精神分裂症患者对S1和S2的P50反应的算术平均波幅相似。同样的测量方法也消除了两组S1和S2平均P50波幅的差异。时间变异性似乎是评估平均EP的一个重要因素，因此导致了精神分裂症中观察到的P50波幅变化。
