Tallon-Baudry C, Bertrand O, Pernier J
Mental Processes and Brain Activation, Institut National de la Santé et de la Recherche Médicale U280, Lyon, France.
Clin Neurophysiol. 1999 Apr;110(4):660-5. doi: 10.1016/s1388-2457(98)00008-x.
As opposed to slow waves, spontaneous and stimulus-induced oscillations in the gamma-band show no polarity reversal in cortical depth, which cannot be explained by the classical equivalent current dipole model usually proposed as a model of pyramidal cell synaptic activity. Here we propose a ring-shaped distribution of dipoles as a source model for these fast oscillations. This distribution generates a field potential that does not reverse through cortical depth. Such a geometry could correspond to horizontally oriented dendritic fields. Moreover, this distribution generates a potential field, but no, or weak, magnetic field on the scalp surface, which corresponds to the observation that visually-induced gamma-band oscillations are detectable in EEG data, but not in simultaneously recorded MEG data.
与慢波相反，γ波段的自发振荡和刺激诱发振荡在皮层深度上没有极性反转，这无法用通常作为锥体细胞突触活动模型提出的经典等效电流偶极子模型来解释。在此，我们提出一种偶极子的环形分布作为这些快速振荡的源模型。这种分布产生的场电位不会在皮层深度上反转。这样的几何结构可能对应于水平取向的树突场。此外，这种分布产生一个电位场，但在头皮表面产生的磁场不存在或很弱，这与在脑电图（EEG）数据中可检测到视觉诱发的γ波段振荡，但在同时记录的脑磁图（MEG）数据中却检测不到这一观察结果相符。
