Gutschalk Alexander, Patterson Roy D, Rupp André, Uppenkamp Stefan, Scherg Michael
Department of Neurology, University of Heidelberg, Im Neuenheimer Feld 400, 69120 Heidelberg, Germany.
Neuroimage. 2002 Jan;15(1):207-16. doi: 10.1006/nimg.2001.0949.
Magnetoencephalography was used to investigate the relationship between the sustained magnetic field in auditory cortex and the perception of periodic sounds. The response to regular and irregular click trains was measured at three sound intensities. Two separate sources were isolated adjacent to primary auditory cortex: One, located in lateral Heschl's gyrus, was particularly sensitive to regularity and largely insensitive to sound level. The second, located just posterior to the first in planum temporale, was particularly sensitive to sound level and largely insensitive to regularity. This double dissociation to the same stimuli indicates that the two sources represent separate mechanisms; the first would appear to be involved with pitch perception and the second with loudness. The delay of the offset of the sustained field was found to increase with interclick interval up to 200 ms at least, which suggests that the sustained field offset represents a sophisticated offset-monitoring mechanism rather than simply the cessation of stimulation.
采用脑磁图技术研究听觉皮层持续磁场与周期性声音感知之间的关系。在三种声音强度下测量了对规则和不规则滴答声序列的反应。在初级听觉皮层附近分离出两个独立的声源：一个位于外侧颞横回，对规律性特别敏感，对声音强度基本不敏感。另一个位于颞平面中第一个声源的后方，对声音强度特别敏感，对规律性基本不敏感。对相同刺激的这种双重分离表明这两个声源代表不同的机制；第一个似乎与音高感知有关，第二个与响度有关。发现持续磁场偏移的延迟至少在200毫秒内随滴答声间隔增加，这表明持续磁场偏移代表一种复杂的偏移监测机制，而不仅仅是刺激的停止。
