Gurtubay I G, Alegre M, Labarga A, Malanda A, Iriarte J, Artieda J
Clinical Neurophysiology Unit, Department of Neurology, Clínica Universitaria, Facultad de Medicina, Universidad de Navarra, Pamplona, Spain.
Clin Neurophysiol. 2001 Jul;112(7):1219-28. doi: 10.1016/s1388-2457(01)00557-0.
To examine the characteristics of evoked and induced gamma band oscillatory responses occurring during P300 development in an auditory oddball paradigm.
A time-frequency analysis method was applied to an auditory oddball paradigm in 7 healthy subjects. This method combines a multiresolution wavelet algorithm for signal extraction and the Gabor transform to represent the temporal evolution of the selected frequency components. Phase-locked or evoked activity and also non-phase-locked activity were computed for both standard and target stimuli.
The gamma band frequency components differed between target and non-target stimuli processing. The study showed an early and mainly phase-locked oscillatory response appearing around 26--28 ms after both standard and target stimuli onset. This response showed a spectral peak around 44 Hz for both stimuli. A late oscillatory activity peaking at 37 Hz with a latency around 360 ms was observed appearing only for target stimuli. The latency of this late oscillatory activity had a high correlation (P=0.002) to the latency of the P300 wave.
EEG signal analysis with wavelet transform allows the identification of an early oscillatory cortical response in the gamma frequency range, as well as a late P300-related response.
研究在听觉Oddball范式中P300发育过程中诱发和诱导的γ波段振荡反应的特征。
将时频分析方法应用于7名健康受试者的听觉Oddball范式。该方法结合了用于信号提取的多分辨率小波算法和用于表示所选频率成分时间演变的Gabor变换。计算标准刺激和目标刺激的锁相或诱发活动以及非锁相活动。
目标刺激与非目标刺激处理之间的γ波段频率成分有所不同。研究表明，在标准刺激和目标刺激开始后约26-28毫秒出现早期且主要为锁相的振荡反应。两种刺激的该反应在44赫兹左右均出现一个频谱峰值。仅在目标刺激中观察到在37赫兹达到峰值且潜伏期约为360毫秒的晚期振荡活动。该晚期振荡活动的潜伏期与P300波的潜伏期具有高度相关性（P=0.002）。
小波变换脑电图信号分析能够识别γ频率范围内的早期振荡皮质反应以及与P300相关的晚期反应。
