SUBTHRESHOLD OSCILLATIONS AND RESONANT-FREQUENCY IN GUINEA-PIG CORTICAL-NEURONS - PHYSIOLOGY AND MODELING
SUBTHRESHOLD OSCILLATIONS AND RESONANT-FREQUENCY IN GUINEA-PIG CORTICAL-NEURONS - PHYSIOLOGY AND MODELING
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DOI：
10.1113/jphysiol.1995.sp020611
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发表时间：
1995-03-15
影响因子：
5.5
通讯作者：
SEGEV, I
中科院分区：
文献类型：
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作者：
GUTFREUND, Y;YAROM, Y;SEGEV, I
1.细胞内记录是从豚鼠额叶皮层切片中的神经元进行的。在50%的细胞中，持续的阈下电压振荡被长（> 6s）去极化脉冲诱发。这些振荡的峰-峰幅度小于5 mV，频率随去极化从4 Hz（接近静止）增加到20 Hz（30 mV去极化），具有电压依赖性.通过向细胞内注入频率线性变化的正弦电流，研究了振荡和非振荡细胞的阻抗-频率关系。在大多数细胞中，在去极化水平下观察到阻抗幅度（共振行为）的峰值。峰值阻抗的频率（峰值频率）随着去极化从3（接近静止）增加到15 Hz（在30 mV去极化时）。TTX（10（-6）M）的应用显著降低了峰值频率附近的阻抗幅度。然而，阈下振荡以及动作电位完全被TTX阻断。TEA（15 mm）和Cs+（5 mm）则同时消除了阈下振荡和共振行为。用Co2+（5 mM）或Ni 2+（1 mM）代替Ca 2+并不能消除阈下振荡。频率响应曲线中的峰值仅略微降低。一个等电位膜模型，包括一个泄漏电流，一个快速的持续钠电流，一个缓慢的非失活钾电流（与动力学的M-电流）和膜电容，是足以产生电压振荡和谐振行为。K+电流本身的动力学足以产生共振行为。Na+电流放大了峰值阻抗幅度，并且对于产生亚阈值振荡至关重要。该模型正确预测了TTX和TEE应用前后的频率响应行为，以及预期无源阻抗和实验阻抗之间的关系.我们推测，神经元在一定频率下产生电压信号（作为阈下振荡的结果）并优先响应到达相同频率的输入（共振行为）的趋势促进了在该优选频率下的群体活动。
1. Intracellular recordings were made from neurons in slices from guinea-pig frontal cortex. In 50% of the cells, sustained subthreshold voltage oscillations were evoked by long (> 6 s) depolarizing pulses. The peak-to-peak amplitude of these oscillations was less than 5 mV and the frequency was voltage dependent, increasing with depolarization from 4 (near rest) to 20 Hz (at 30 mV depolarization).2. The impedance-frequency relationship of both oscillating and non-oscillating cells was studied by intracellular injection of sinusoidal current with linearly changing frequency. In most cells, a peak in the impedance magnitude (resonant behaviour) was observed at depolarized levels. The frequency of the peak impedance (peak frequency) increased with depolarization from 3 (near rest) to 15 Hz (at 30 mV depolarization).3. Application of TTX (10(-6) M) significantly decreased the impedance magnitude near the peak frequency. The subthreshold oscillations, however, as well as the action potentials, were fully blocked by TTX. On the other hand, TEA (15 mm) and Cs+ (5 mar) abolished both the subthreshold oscillations and the resonant behaviour. Replacing Ca2+ with Co2+ (5 mM) or Ni2+ (1 mM) did not abolish the subthreshold oscillations. The peak in the frequency-response curve was only slightly reduced.4. An isopotential membrane model, consisting of a leak current, a fast persistent sodium current, a slow non-inactivating potassium current (with the kinetics of the M-current) and membrane capacitance, is sufficient to produce both voltage oscillations and resonant behaviour. The kinetics of the K+ current by itself is sufficient to produce resonance behaviour. The Na+ current amplifies the peak impedance magnitude and is essential for the generation of subthreshold oscillation. The model correctly predicted the behaviour of the frequency response before and after TTX and TEE application, as well as the relation between the expected passive impedance and the experimental impedance.5. We speculate that the tendency of the neurons to generate voltage signals at a certain frequency (as a result of the subthreshold oscillations) and to preferentially respond to inputs arriving at the same frequency (the resonance behaviour) promotes population activity at that preferred frequency.