Pollok Bettina, Moll Marek, Schmitz Frank, Müller Katharina, Schnitzler Alfons
Max Planck Institute for Psychological Research, Munich, Germany.
Neuroreport. 2002 Feb 11;13(2):235-8. doi: 10.1097/00001756-200202110-00012.
We analyzed somatosensory evoked steady-state fields in order to localize finger representations in the hand area of the primary somatosensory cortex (S1). Using a 122-channel whole-head neuromagnetometer we recorded in six healthy subjects neuromagnetic responses to high frequency electrical stimuli delivered simultaneously to digit I, II, III and V at 22, 24, 27 and 30 Hz, respectively, and to transient stimulation of each single digit with a frequency of 3 Hz. Responses were averaged separately for each digit and were modeled by single equivalent current dipoles. Both conditions yielded the typical somatotopic finger representations within S1 hand area. Dipole locations did not differ significantly between the transient and the steady-state stimulation. Therefore, simultaneous high-frequency stimulation of the digits seems to be a reliable method for rapid and detailed mapping of the S1 hand area. This procedure has potential advantages over recording of transient responses. With simultaneous steady-state stimulation the measurement times are reduced to 2 min for mapping the whole hand area. Because of this our method probably increases spatial accuracy and permits repeated short interval recordings, e.g. in experiments studying short term plasticity.
我们分析了体感诱发稳态场，以便在初级体感皮层（S1）的手部区域定位手指表征。我们使用一台122通道的全头神经磁强计，记录了6名健康受试者对分别以22、24、27和30Hz的频率同时施加于食指、中指、无名指和小指的高频电刺激，以及对每个单指以3Hz频率进行的瞬态刺激的神经磁反应。对每个手指的反应分别进行平均，并通过单个等效电流偶极子进行建模。两种条件均在S1手部区域产生了典型的躯体感觉手指表征。瞬态刺激和稳态刺激之间的偶极子位置没有显著差异。因此，手指的同时高频刺激似乎是一种快速、详细绘制S1手部区域图谱的可靠方法。该程序相对于记录瞬态反应具有潜在优势。通过同时进行稳态刺激，绘制整个手部区域的测量时间可缩短至2分钟。因此，我们的方法可能提高空间精度，并允许重复进行短时间间隔记录，例如在研究短期可塑性的实验中。
