ICBM, University of Oldenburg, Oldenburg, Germany.
Neural Comput. 2010 Mar;22(3):599-620. doi: 10.1162/neco.2009.01-09-934.
The property of a neuron to phase-lock to an oscillatory stimulus before adapting its spike rate to the stimulus frequency plays an important role for the auditory system. We investigate under which conditions neurons exhibit this phase locking below rate threshold. To this end, we simulate neurons employing the widely used leaky integrate-and-fire (LIF) model. Tuning parameters, we can arrange either an irregular spontaneous or a tonic spiking mode. When the neuron is stimulated in both modes, a significant rise of vector strength prior to a noticeable change of the spike rate can be observed. Combining analytic reasoning with numerical simulations, we trace this observation back to a modulation of interspike intervals, which itself requires spikes to be only loosely coupled. We test the limits of this conception by simulating an LIF model with threshold fatigue, which generates pronounced anticorrelations between subsequent interspike intervals. In addition we evaluate the LIF response for harmonic stimuli of various frequencies and discuss the extension to more complex stimuli. It seems that phase locking below rate threshold occurs generically for all zero mean stimuli. Finally, we discuss our findings in the context of stimulus detection.
神经元在适应刺激频率之前将其尖峰率相位锁定到振荡刺激的特性对听觉系统起着重要作用。我们研究了神经元在低于率阈值的情况下表现出这种相位锁定的条件。为此，我们使用广泛使用的漏积分和放电 (LIF) 模型来模拟神经元。通过调整调谐参数，我们可以安排不规则的自发或紧张的尖峰模式。当神经元在这两种模式下受到刺激时，在明显改变尖峰率之前，可以观察到向量强度的显著上升。通过将分析推理与数值模拟相结合，我们将这种观察归因于尖峰间隔的调制，而尖峰间隔本身需要尖峰仅松散耦合。我们通过模拟具有阈值疲劳的 LIF 模型来测试这个概念的限制，该模型会在后续尖峰间隔之间产生明显的反相关。此外，我们还评估了 LIF 对各种频率的谐波刺激的响应，并讨论了对更复杂刺激的扩展。似乎在低于率阈值的情况下，所有零均值刺激都会普遍出现相位锁定。最后，我们在刺激检测的背景下讨论了我们的发现。
