Aine C J, Supek S, George J S
Biophysics Group, Los Alamos National Laboratory, NM 87545, USA.
Int J Neurosci. 1995;80(1-4):79-104. doi: 10.3109/00207459508986095.
Results are reviewed from several neuromagnetic studies which characterize the temporal dynamics of neural sources contributing to the visual evoked response and effects of attention on these sources. Different types of pattern-onset stimuli (< or = 2 degrees) were presented sequentially to a number of field locations in the right visual field. Multiple dipole models were applied to a sequence of instantaneous field distributions constructed at 10 ms intervals. Best-fitting source parameters were superimposed on Magnetic Resonance images (MRI) of each subject to identify the anatomical structure(s) giving rise to the surface patterns. At least three sources, presumably corresponding to different visual areas, were routinely identified from 80-150 ms following the onset of visual stimulation. This observation was consistent across subjects and studies. The temporal sequence and strength of activation of these sources, however, were dependent upon the specific stimulus parameters used to evoke the response (e.g., eccentricity) and on the relevance of the stimulus to the subject. In addition, our results provide evidence for the recurrence of activity in striate and extrastriate regions, following the initial cycle of responses.
本文回顾了多项神经磁学研究的结果，这些研究描述了对视觉诱发反应有贡献的神经源的时间动态变化以及注意力对这些神经源的影响。不同类型的图案起始刺激（≤2度）被依次呈现给右视野中的多个视野位置。多偶极子模型被应用于以10毫秒间隔构建的一系列瞬时场分布。将最佳拟合源参数叠加在每个受试者的磁共振图像（MRI）上，以识别产生表面图案的解剖结构。在视觉刺激开始后的80 - 150毫秒内，通常可识别出至少三个可能对应于不同视觉区域的神经源。这一观察结果在不同受试者和研究中是一致的。然而，这些神经源激活的时间序列和强度取决于用于诱发反应的特定刺激参数（如偏心率）以及刺激与受试者的相关性。此外，我们的结果为在最初的反应周期之后，纹状区和纹状外区活动的复发提供了证据。
