Spatiotemporal patterns of dorsal root-evoked network activity in the neonatal rat spinal cord: optical and intracellular recordings.
Spatiotemporal patterns of dorsal root-evoked network activity in the neonatal rat spinal cord: optical and intracellular recordings.
复制标题
新生大鼠脊髓背根诱发网络活动的时空模式：光学和细胞内记录。
DOI：
10.1152/jn.00209.2005
复制
发表时间：
2005
期刊：
影响因子：
--
通讯作者：
Redman,Stephen
中科院分区：
文献类型：
--
作者：
Ziskind-Conhaim,Lea;Redman,Stephen
通过使用多光电二极管光学相机监测电压敏感染料的光信号，研究了大鼠脊髓横向切片的背根诱发电位的时空模式。通常，背根刺激会产生两种基本的电压图像波形：双分量图像，由背角中的快速、尖峰状信号和随后的慢信号组成，以及腹角中的小而慢的信号。为了定性地将光信号与膜电位联系起来，将全细胞记录与体细胞周围区域的光吸收测量相结合。慢光信号与脊髓所有区域的阈下突触后电位密切相关。尖峰状成分与突触后动作电位无关，表明快速信号是由突触前动作电位产生的。单个神经元的放电无法通过光学方式检测到，这意味着局部电压图像源自同步激活的神经元群。阻断谷氨酸突触传递会抑制兴奋性突触后电位（EPSP）并显着减少慢光信号，表明它们是由谷氨酸突触介导的。抑制甘氨酸介导的抑制作用增加了光信号和 EPSP 的振幅，同时阻断 GABAA 受体介导的突触，增加了 EPSP 的振幅和时间过程，并延长了切片较大区域中电压图像的持续时间。诱发的 EPSP 与其各自的局部电压图像之间的密切相关性表明了高时间分辨率光学系统在测量节段网络激励的时空动态和识别位点神经元集合的积分电位方面的优势。
Spatiotemporal patterns of dorsal root–evoked potentials were studied in transverse slices of the rat spinal cord by monitoring optical signals from a voltage-sensitive dye with multiple-photodiode optic camera. Typically, dorsal root stimulation generated two basic waveforms of voltage images: dual-component images consisting of fast, spike-like signal followed by a slow signal in the dorsal horn, and small, slow signals in the ventral horn. To qualitatively relate the optical signals to membrane potentials, whole cell recordings were combined with measurements of light absorption in the area around the soma. The slow optical signals correlated closely with subthreshold postsynaptic potentials in all regions of the cord. The spike-like component was not associated with postsynaptic action potentials, suggesting that the fast signal was generated by presynaptic action potentials. Firing in a single neuron could not be detected optically, implying that local voltage images originated from synchronously activated neuronal ensembles. Blocking glutamatergic synaptic transmission inhibited excitatory postsynaptic potentials (EPSPs) and significantly reduced the slow optical signals, indicating that they were mediated by glutamatergic synapses. Suppressing glycine-mediated inhibition increased the amplitude of both optical signals and EPSPs, while blocking GABAAreceptor–mediated synapses, increased the amplitude and time course of EPSPs and prolonged the duration of voltage images in larger areas of the slice. The close correlation between evoked EPSPs and their respective local voltage images shows the advantage of the high temporal resolution optical system in measuring both the spatiotemporal dynamics of segmental network excitation and integrated potentials of neuronal ensembles at identified sites.