An Evaluation of the Conductivity Profile in the Somatosensory Barrel Cortex of Wistar Rats
An Evaluation of the Conductivity Profile in the Somatosensory Barrel Cortex of Wistar Rats
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DOI：
10.1152/jn.00122.2010
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发表时间：
2010-12-01
影响因子：
2.5
通讯作者：
Kawashima, Ryuta
中科院分区：
文献类型：
--
作者：
Goto, Takakuni;Hatanaka, Rieko;Kawashima, Ryuta
郭东东，Hatanaka R，Ogawa T，Sumiyoshi A，Riera J，Kawashima R.Wistar大鼠躯体感觉桶皮质电导的评估。神经生理学杂志104：3388-3412,2010。2010年9月1日首次出版；DOI：10.1152/jn.00122.2010。用于记录大脑局部场电位的微电极阵列正在以越来越高的空间分辨率建造，从最初开发的层状阵列到平面和三维(3D)格式的微电极阵列。随着记录技术的发展，电流源密度(CSD)分析最近已经扩展到连续3D形式。不幸的是，电导率分布对当代微电极阵列CSD分析的影响还没有得到评估，大多数研究都假设它是均匀的和各向同性的。在本研究中，我们测量了Wistar大鼠躯体感觉桶皮质的电导分布。为此，我们将自制的硅基探头组件记录的多点电生理数据与非线性最小二乘算法相结合，该算法隐含地假设啮齿动物的大脑皮层可以局部近似为分层的各向异性球形体积导体。从死后组织学图像评价躯体感觉桶皮质六层皮质的偏心率。我们为具有同心皮质层的整个桶油田的局部球状特征提供了证据。我们发现电导值与径向/切向各向异性之间存在显著的层流依赖关系。这些结果与有髓轴突的层相关方向一致，但与细胞密度几乎无关。最后，我们通过模拟证明，忽略大鼠躯体感觉桶皮质的真实电导分布会导致CSD重建中的相当大的误差，对连续3D形式和电荷不平衡的CSD有显著的影响。我们的结论是，电导率谱必须包括在CSD分析的未来发展中，特别是对啮齿动物。
Goto T, Hatanaka R, Ogawa T, Sumiyoshi A, Riera J, Kawashima R. An evaluation of the conductivity profile in the somatosensory barrel cortex of Wistar rats. J Neurophysiol 104: 3388-3412, 2010. First published September 1, 2010; doi:10.1152/jn.00122.2010. Microelectrode arrays used to record local field potentials from the brain are being built with increasingly more spatial resolution, ranging from the initially developed laminar arrays to those with planar and three-dimensional (3D) formats. In parallel with such development in recording techniques, current source density (CSD) analyses have recently been expanded up to the continuous-3D form. Unfortunately, the effect of the conductivity profile on the CSD analysis performed with contemporary microelectrode arrays has not yet been evaluated and most of the studies assumed it was homogeneous and isotropic. In this study, we measured the conductivity profile in the somatosensory barrel cortex of Wistar rats. To that end, we combined multisite electrophysiological data recorded with a homemade assembly of silicon-based probes and a nonlinear least-squares algorithm that implicitly assumed that the cerebral cortex of rodents could be locally approximated as a layered anisotropic spherical volume conductor. The eccentricity of the six cortical layers in the somatosensory barrel cortex was evaluated from postmortem histological images. We provided evidence for the local spherical character of the entire barrels field, with concentric cortical layers. We found significant laminar dependencies in the conductivity values with radial/tangential anisotropies. These results were in agreement with the layer-dependent orientations of myelinated axons, but hardly related to densities of cells. Finally, we demonstrated through simulations that ignoring the real conductivity profile in the somatosensory barrel cortex of rats caused considerable errors in the CSD reconstruction, with pronounced effects on the continuous-3D form and charge-unbalanced CSD. We concluded that the conductivity profile must be included in future developments of CSD analysis, especially for rodents.