High-Frequency Resonance in the Gerbil Medial Superior Olive.
High-Frequency Resonance in the Gerbil Medial Superior Olive.
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DOI：
10.1371/journal.pcbi.1005166
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发表时间：
2016-11
影响因子：
4.3
通讯作者：
Rinzel J
中科院分区：
文献类型：
--
作者：
Mikiel-Hunter J;Kotak V;Rinzel J
最近，豚鼠内侧上级橄榄（MSO）的高频阈下共振与从声学刺激的精细结构中有效提取空间线索有关。我们在这里报告，沙鼠的MSO神经元也有共振特性，并根据我们的全细胞记录和计算建模，低电压门控钾电流，IKLT，是共振的基础。我们表明，在用漏电导动态钳位取代IKLT后，以及在模型中，当IKLT的电压门控被抑制时，谐振就会消失。谐振的特点是使用小振幅正弦刺激，以产生阻抗曲线，通常做线性系统分析。将我们的研究扩展到非线性、电压依赖性机制，我们增加刺激幅度，并在实验和模拟中发现，阈下共振频率（弱刺激为242 Hz）连续增加到尖峰（285 Hz）的共振频率。这些相位放电（III型可兴奋）MSO神经元和模型的尖峰共振也特别令人感兴趣，因为以前的共振研究通常涉及神经元/模型（II型可兴奋，如标准的Hodgkin-Huxley模型），这些神经元/模型可以对稳定的输入进行紧张性放电。为了更直接地探索这些共振如何与作为斜率检测器的MSO神经元相关，我们向模型呈现了周期性的短暂的快速上升的兴奋性突触后电位（EPSC）。虽然弱阈下EPSC列车基本上是低通滤波，共振出现EPSC振幅增加。有趣的是，对于诱发尖峰的EPSC串，在尖峰共振频率（317 Hz）处的阈值幅度低于单个ESPC阈值。我们发现的频率依赖性阈值的重复性短暂的EPSC刺激和首选频率的尖峰呼吁进一步考虑阈下和阈上共振的快速和精确的时间处理中的MSO。内侧上级橄榄（MSO）的主要神经元是参与声音定位的神经元计算的快速和精确的符合探测器。我们表明，他们表现出共振特性在体外，响应小的振荡输入，最大限度地在首选频率。它们的共振频率很高，几乎是皮层或海马神经元的100倍。我们使用电生理记录（沙鼠MSO）和计算建模来识别这种快速共振的关键生物物理因素：低阈值钾电流IKLT，其激活时间常数略低于膜时间常数（τm <1 ms）。MSO神经元的共振频率随着刺激振幅而增加，并且接近以最低刺激振幅引起尖峰的优选频率。在我们的神经元模型中，阈下和阈上共振之间的这种关系也适用于短暂的类突触输入，即使对弱阈下突触输入的响应进行了低通滤波。我们的研究结果表明，刺激幅度和波形，和IKLT，测量阻抗，因此共振的重要影响。此外，我们的数据突出的可能性，即使是短暂的突触输入可能会选择性过滤的内在生物物理特性的MSO神经元。
A high-frequency, subthreshold resonance in the guinea pig medial superior olive (MSO) was recently linked to the efficient extraction of spatial cues from the fine structure of acoustic stimuli. We report here that MSO neurons in gerbil also have resonant properties and, based on our whole-cell recordings and computational modeling, that a low-voltage-gated potassium current, IKLT, underlies the resonance. We show that resonance was lost following dynamic clamp replacement of IKLT with a leak conductance and in the model when voltage-gating of IKLT was suppressed. Resonance was characterized using small amplitude sinusoidal stimuli to generate impedance curves as typically done for linear systems analysis. Extending our study into the nonlinear, voltage-dependent regime, we increased stimulus amplitude and found, experimentally and in simulations, that the subthreshold resonant frequency (242Hz for weak stimuli) increased continuously to the resonant frequency for spiking (285Hz). The spike resonance of these phasic-firing (type III excitable) MSO neurons and of the model is of particular interest also because previous studies of resonance typically involved neurons/models (type II excitable, such as the standard Hodgkin-Huxley model) that can fire tonically for steady inputs. To probe more directly how these resonances relate to MSO neurons as slope-detectors, we presented periodic trains of brief, fast-rising excitatory post-synaptic potentials (EPSCs) to the model. While weak subthreshold EPSC trains were essentially low-pass filtered, resonance emerged as EPSC amplitude increased. Interestingly, for spike-evoking EPSC trains, the threshold amplitude at spike resonant frequency (317Hz) was lower than the single ESPC threshold. Our finding of a frequency-dependent threshold for repetitive brief EPSC stimuli and preferred frequency for spiking calls for further consideration of both subthreshold and suprathreshold resonance to fast and precise temporal processing in the MSO. Principal neurons of the medial superior olive (MSO) are fast and precise coincidence detectors involved in the neuronal computation of sound localization. We show that they exhibit resonance properties in vitro, responding to small oscillatory inputs, maximally at preferred frequencies. Their resonant frequencies are high, nearly a hundred-fold that found in cortical or hippocampal neurons. We used electrophysiological recordings (gerbil MSO) and computational modelling to identify the key biophysical factors for this fast resonance: a low-threshold potassium current, IKLT, whose activation time constant is slightly slower than the membrane time constant (τm < 1ms). An MSO neuron’s resonant frequency increases with stimulus amplitude and approaches the preferred frequency at which spiking is elicited with the lowest stimulus amplitude. This relationship between subthreshold and suprathreshold resonances also holds for trains of brief synaptic-like inputs in our neuron model, even though responses for weak subthreshold synaptic inputs are low-pass filtered. Our results demonstrate the important effects of stimulus amplitude and waveform, and IKLT, on measurements of impedance and therefore resonance. In addition, our data highlight the possibility that even brief synaptic input may be selectively filtered by the intrinsic biophysical properties of MSO neurons.
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影响因子：
9.8
作者：
Jercog PE;Svirskis G;Kotak VC;Sanes DH;Rinzel J
通讯作者：
Rinzel J
影响因子：
5.5
作者：
Magnusson, AK;Kapfer, C;Koch, U
通讯作者：
Koch, U
影响因子：
2.5
作者：
PUIL, E;GIMBARZEVSKY, B;MIURA, RM
通讯作者：
MIURA, RM
DOI：
10.1007/s00359-015-1036-1
发表时间：
2015-11-01
影响因子：
2.1
作者：
Rau, Florian;Clemens, Jan;Schreiber, Susanne
通讯作者：
Schreiber, Susanne
影响因子：
5.5
作者：
HODGKIN, AL
通讯作者：
HODGKIN, AL