Genesis of MEG signals in a mammalian CNS structure
Genesis of MEG signals in a mammalian CNS structure
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DOI：
10.1016/s0013-4694(97)00043-6
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发表时间：
1997-10-01
期刊：
影响因子：
--
通讯作者：
Kyuhou, S
中科院分区：
文献类型：
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作者：
Okada, YC;Wu, J;Kyuhou, S
本研究对豚鼠海马脑片的神经磁信号进行了表征，并与细胞外场电位进行了比较，以阐明哺乳动物中枢神经系统结构中脑磁信号的起源。在阻断抑制性突触传递的0.1 mM印防己毒素（PTX）存在下，横向CA1、纵向CA1和纵向CA3脑片垂直于浴面方向的磁诱发场（MEF）的空间分布相似，它们的MEF是由沿着锥体细胞纵轴的电流产生的。与层流电位曲线的MEF的比较表明，MEF产生的细胞内纵向电流。细胞内电流的偶极分量是产生MEF的主导因素，即使在距离切片2 mm处。来自无PTX的林格氏溶液中的切片的MEF在时间波形上变得与PTX存在下的MEF相似，这表明兴奋性连接在产生MEF中占优势，并且即使在无PTX的林格氏溶液中也存在跨切片的高度同步的群体活动。这种高度同步的人口活动的存在下的MEFs直接验证与记录在整个切片的场电位。刺激部位的系统变化揭示了每个部位的特征波形。波形随刺激部位的变化表明，许多因素的贡献，突触和电压敏感的电导，MEF的整体波形。(C)1997 Elsevier Science爱尔兰有限公司
Neuromagnetic signals of guinea pig hippocampal slices were characterized and compared with the extracellular field potential to elucidate the genesis of magnetoencephalographic signals in a mammalian CNS structure. The spatial distribution of magnetic evoked field (MEF) directed normal to bath surface was similar for transverse CA1, longitudinal CA1 and longitudinal CA3 slices in the presence of 0.1 mM picrotoxin (PTX) which blocks inhibitory synaptic transmission; Their MEFs were produced by currents along the longitudinal axis of the pyramidal cells. Comparisons of the MEF with the laminar potential profile revealed that the MEF was generated by intracellular longitudinal currents. The dipolar component of the intracellular currents was the dominant factor generating the MEF even at a distance of 2 mm from the slice. The MEF from a slice in Ringer's solution without PTX became similar in temporal waveform with time to the MEF in the presence of PTX, indicating the predominance of excitatory connections in generating the MEF and the existence of highly synchronous population activities across the slice even in PTX-free Ringer's solution. The presence of such highly synchronous population activities underlying the MEFs was verified directly with field potentials recorded across the slice. A systematic Variation of the stimulation site revealed a characteristic waveform for each site. The variation of the waveform with stimulation site suggested the contribution of many factors, both synaptic and voltage-sensitive conductances, to the overall waveform of the MEF. (C) 1997 Elsevier Science Ireland Ltd.