Stanley Laboratory of Electrical Physics, Great Barrington, Massachusetts, United States of America.
PLoS One. 2011;6(8):e23412. doi: 10.1371/journal.pone.0023412. Epub 2011 Aug 10.
Pyramidal neurons of the neocortex display a wide range of synchronous EEG rhythms, which arise from electric activity along the apical dendrites of neocortical pyramidal neurons. Here we present a theoretical description of oscillation frequency profiles along apical dendrites which exhibit resonance frequencies in the range of 10 to 100 Hz. The apical dendrite is modeled as a leaky coaxial cable coated with a dielectric, in which a series of compartments act as coupled electric circuits that gradually narrow the resonance profile. The tuning of the peak frequency is assumed to be controlled by the average amplitude of voltage-gated outward currents, which in turn are regulated by the subthreshold noise in the thousands of synaptic spines that are continuously bombarded by local circuits. The results of simulations confirmed the ability of the model both to tune the peak frequency in the 10-100 Hz range and to gradually narrow the resonance profile. Considerable additional narrowing of the resonance profile is provided by repeated looping through the apical dendrite via the corticothalamocortical circuit, which reduced the width of each resonance curve (at half-maximum) to approximately 1 Hz. Synaptic noise in the neural circuit is discussed in relation to the ways it can influence the narrowing process.
新皮层的锥体神经元显示出广泛的同步 EEG 节律，这些节律源于新皮层锥体神经元的顶树突的电活动。在这里，我们提出了一种理论描述，描述了在表现出 10 到 100 Hz 范围内共振频率的顶树突上的振荡频率分布。顶树突被建模为一个漏同轴电缆，其上覆盖有介电层，其中一系列隔室充当耦合电路，这些电路逐渐使共振轮廓变窄。峰值频率的调谐被假定由电压门控外向电流的平均幅度控制，而外向电流反过来又受到数千个突触棘突中亚阈值噪声的调节，这些突触棘突不断受到局部回路的冲击。模拟的结果证实了该模型在 10-100 Hz 范围内调谐峰值频率并逐渐使共振轮廓变窄的能力。通过通过皮质丘脑皮质回路在顶树突上反复循环，进一步大大缩小了共振轮廓，从而使每个共振曲线（在半最大值处）的宽度减小到约 1 Hz。讨论了神经电路中的突触噪声如何影响变窄过程。
