Lenz Daniel, Schadow Jeanette, Thaerig Stefanie, Busch Niko A, Herrmann Christoph S
Department of Biological Psychology, Otto-von-Guericke University of Magdeburg, P.O. Box 4120, 39016 Magdeburg, Germany.
Int J Psychophysiol. 2007 Apr;64(1):31-8. doi: 10.1016/j.ijpsycho.2006.07.008. Epub 2006 Sep 7.
In recent years the cognitive functions of human gamma-band activity (30-100 Hz) advanced continuously into scientific focus. Not only bottom-up driven influences on 40 Hz activity have been observed, but also top-down processes seem to modulate responses in this frequency band. Among the various functions that have been related to gamma activity a pivotal role has been assigned to memory processes. Visual experiments suggested that gamma activity is involved in matching visual input to memory representations. Based on these findings we hypothesized that such memory related modulations of gamma activity exist in the auditory modality, as well. Thus, we chose environmental sounds for which subjects already had a long-term memory (LTM) representation and compared them to unknown, but physically similar sounds. 21 subjects had to classify sounds as 'recognized' or 'unrecognized', while EEG was recorded. Our data show significantly stronger activity in the induced gamma-band for recognized sounds in the time window between 300 and 500 ms after stimulus onset with a central topography. The results suggest that induced gamma-band activity reflects the matches between sounds and their representations in auditory LTM.
近年来，人类γ波段活动（30 - 100赫兹）的认知功能不断成为科学关注的焦点。不仅观察到了自下而上对40赫兹活动的驱动影响，而且自上而下的过程似乎也在调节该频段的反应。在与γ活动相关的各种功能中，记忆过程被赋予了关键作用。视觉实验表明，γ活动参与将视觉输入与记忆表征进行匹配。基于这些发现，我们推测这种与记忆相关的γ活动调制在听觉模态中也存在。因此，我们选择了受试者已经有长期记忆（LTM）表征的环境声音，并将它们与未知但物理上相似的声音进行比较。21名受试者在记录脑电图（EEG）的同时，必须将声音分类为“已识别”或“未识别”。我们的数据显示，在刺激开始后300至500毫秒的时间窗口内，对于已识别声音，诱发γ波段的活动显著更强，且具有中央分布特征。结果表明，诱发γ波段活动反映了声音与其在听觉LTM中的表征之间的匹配。
