Hirai Masahiro, Kaneoke Yoshiki, Nakata Hiroki
Department of Integrative Physiology, National Institute for Physiological Sciences, 38 Nishigonaka, Myoudaiji, Okazaki, 444-8585, Japan; Japan Society for the Promotion of Science (JSPS), Japan.
Clin Neurophysiol. 2008 Dec;119(12):2775-84. doi: 10.1016/j.clinph.2008.09.008. Epub 2008 Oct 18.
The aim of this study is to extract magnetoencephalographic responses relating to the processing of point-light walker (PLW).
To attenuate neural activities in the lower visual areas, we presented a scrambled-PLW as a first stimulus and then either an upright- or inverted-PLW/scrambled-PLW as a second stimulus. Each point of the scrambled-PLW stimulus had the same velocity vector as the points of the PLW stimulus, but points were interchanged randomly.
The peak neuromagnetic response to the first stimulus was observed at around 250ms after stimulus onset, whereas the peak latency in response to second stimulus was around 350ms after stimulus onset. The peak amplitude induced by the PLW stimulus was significantly larger than that by the scrambled-PLW during the second stimulus. Moreover, the signal source of the responses to the PLW was estimated to lie in the occipitotemporal region, more anterior than the source of the response to the first stimulus.
These findings indicate that the response to the first stimulus reflects general motion processing, while responses to the second stimuli are involved in PLW processing.
This is the first evidence to specify a single neuromagnetic response to a PLW stimulus.
本研究旨在提取与光点步行者（PLW）加工相关的脑磁图反应。
为减弱较低视觉区域的神经活动，我们先呈现一个打乱的PLW作为第一个刺激，然后再呈现一个直立或倒置的PLW/打乱的PLW作为第二个刺激。打乱的PLW刺激的每个点与PLW刺激的点具有相同的速度矢量，但点是随机互换的。
对第一个刺激的峰值神经磁反应在刺激开始后约250毫秒观察到，而对第二个刺激的峰值潜伏期在刺激开始后约350毫秒。在第二个刺激期间，PLW刺激诱发的峰值幅度明显大于打乱的PLW刺激诱发的峰值幅度。此外，对PLW反应的信号源估计位于枕颞区，比第一个刺激反应的源更靠前。
这些发现表明，对第一个刺激的反应反映了一般运动加工，而对第二个刺激的反应参与了PLW加工。
这是首次明确对PLW刺激的单一神经磁反应的证据。
