Conditional Bursting Enhances Resonant Firing in Neocortical Layer 2-3 Pyramidal Neurons
Conditional Bursting Enhances Resonant Firing in Neocortical Layer 2-3 Pyramidal Neurons
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DOI：
10.1523/jneurosci.3728-08.2009
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发表时间：
2009-02-04
影响因子：
5.3
通讯作者：
Spain, William J.
中科院分区：
文献类型：
--
作者：
Higgs, Matthew H.;Spain, William J.
神经元的频率响应特性对于信号传输和网络振荡控制至关重要。在阈下膜电位下，一些神经元表现出由电压门控通道引起的共振。在动作电位放电期间，尖峰输出的谐振可能由亚阈值机制和/或尖峰相关电流引起，导致后超极化 (AHP) 和后去极化 (ADP)。第 2-3 层锥体神经元 (L2-3 PN) 具有可以触发突发的快速 ADP。本研究调查了哪些刺激会引起这些细胞的爆发，以及爆发是否传输突触输入的特定频率成分，从而导致特定频率的共振。我们发现双尖峰突发是由阶跃起始、两个频带中的正弦波和噪声触发的。使用调整为以类似于 10 Hz 的频率引发发射的噪声，我们测量了随刺激频率变化的时变发射率调制增益，发现主峰 (7-16 Hz) 和高频共振 (250-450 Hz)。还分别测量了单次尖峰和突发尖峰的增益。对于给定的尖峰速率，突发在主峰处提供更高的增益，在中频处提供更低的增益，从而锐化高频谐振。使用自动电流反馈抑制爆发削弱了初级和高频谐振。初级共振还受到 SK 通道介导的介质 AHP (mAHP) 的影响，因为 SK 阻滞剂 apamin 降低了初级峰的锐度。我们的结果表明 L2-3 PN 中的共振取决于爆发放电和 mAHP。突发增强了两个不同频段的共振。
The frequency response properties of neurons are critical for signal transmission and control of network oscillations. At subthreshold membrane potential, some neurons show resonance caused by voltage-gated channels. During action potential firing, resonance of the spike output may arise from subthreshold mechanisms and/or spike-dependent currents that cause afterhyperpolarizations (AHPs) and afterdepolarizations (ADPs). Layer 2-3 pyramidal neurons (L2-3 PNs) have a fast ADP that can trigger bursts. The present study investigated what stimuli elicit bursting in these cells and whether bursts transmit specific frequency components of the synaptic input, leading to resonance at particular frequencies. We found that two-spike bursts are triggered by step onsets, sine waves in two frequency bands, and noise. Using noise adjusted to elicit firing at similar to 10 Hz, we measured the gain for modulation of the time-varying firing rate as a function of stimulus frequency, finding a primary peak (7-16 Hz) and a high-frequency resonance (250-450 Hz). Gain was also measured separately for single and burst spikes. For a given spike rate, bursts provided higher gain at the primary peak and lower gain at intermediate frequencies, sharpening the high-frequency resonance. Suppression of bursting using automated current feedback weakened the primary and high-frequency resonances. The primary resonance was also influenced by the SK channel-mediated medium AHP (mAHP), because the SK blocker apamin reduced the sharpness of the primary peak. Our results suggest that resonance in L2-3 PNs depends on burst firing and the mAHP. Bursting enhances resonance in two distinct frequency bands.