Lee Bumsuk, Kaneoke Yoshiki, Kakigi Ryusuke, Sakai Yasujiro
Department of Occupational Therapy, School of Health Sciences, Gunma University, Maebashi 371-8514, Japan.
Int J Psychophysiol. 2009 Nov;74(2):81-7. doi: 10.1016/j.ijpsycho.2009.07.005. Epub 2009 Jul 28.
We studied the human brain response to visual stimulation in which a square area was randomly presented in upper and lower visual fields (VFs). Seven normal volunteers carried out a contrast-based visual search task. Magnetic responses were detected in the bilateral parietal regions at 200-250 ms after stimulus onset. We compared the response latencies and strengths of the essential single sensor and root mean square (RMS) of the regions. The former evaluates the strength of neural activity with relatively high spatial resolution, while the latter evaluates the global neural activity. The single sensor and RMS latencies for the lower left VF were significantly longer than that for the upper left (paired t-test, P<0.05). The strengths did not differ between the upper and lower left VFs. There was no significant difference in latency or strength between the upper right and lower right VFs. These findings suggest that only left VF has different response properties in the upper versus lower VF, and that both local and global extrastriate activities are responsible for this anisotropy.
我们研究了人类大脑对视觉刺激的反应，其中一个方形区域在上下视野（VF）中随机呈现。七名正常志愿者进行了基于对比度的视觉搜索任务。在刺激开始后200 - 250毫秒，在双侧顶叶区域检测到磁反应。我们比较了这些区域基本单传感器的反应潜伏期和强度以及均方根（RMS）。前者以相对较高的空间分辨率评估神经活动的强度，而后者评估整体神经活动。左下视野的单传感器和RMS潜伏期明显长于左上视野（配对t检验，P<0.05）。左上和左下视野之间的强度没有差异。右上和右下视野之间在潜伏期或强度上没有显著差异。这些发现表明，只有左视野在上视野和下视野中具有不同的反应特性，并且局部和整体纹外活动是这种各向异性的原因。
