Dynamical Response Properties of Neocortical Neuron Ensembles: Multiplicative versus Additive Noise
Dynamical Response Properties of Neocortical Neuron Ensembles: Multiplicative versus Additive Noise
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DOI：
10.1523/jneurosci.3424-08.2009
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发表时间：
2009-01-28
影响因子：
5.3
通讯作者：
Naundorf, Bjoern
中科院分区：
文献类型：
--
作者：
Boucsein, Clemens;Tetzlaff, Tom;Naundorf, Bjoern
为了理解大脑中快速信息处理的机制，有必要确定神经元群体在嘈杂环境中对传入刺激的反应速度。最近，它已被实验证明，一个合奏的新皮层神经元可以跟踪随时间变化的输入电流在加性相关噪声的存在非常快，高达几百赫兹的频率。然而，突触前神经元群体的放电率的调制不仅影响到突触后细胞的突触输入的均值，而且还影响到突触后细胞的方差。有人认为，这种噪声强度的调制（乘法调制）可以比平均输入电流的调制（加法调制）更快地跟踪。在这里，我们比较了两种调制方案的新皮层神经元的合奏的响应特性。我们将正弦调制的噪声电流（加性和乘性调制）注入大鼠体感皮质的第V层锥体神经元，并测量了各种刺激频率的试验和系综平均锋电位反应。对于这两种调制模式，我们观察到低通行为。截止频率非常高，大大高于平均放电率。我们证明，调制的方差可以跟踪显着快于调制的平均输入。如果刺激幅度足够高，则可以可靠地跟踪极快的刺激（高达1 kHz）。
To understand the mechanisms of fast information processing in the brain, it is necessary to determine how rapidly populations of neurons can respond to incoming stimuli in a noisy environment. Recently, it has been shown experimentally that an ensemble of neocortical neurons can track a time-varying input current in the presence of additive correlated noise very fast, up to frequencies of several hundred hertz. Modulations in the firing rate of presynaptic neuron populations affect, however, not only the mean but also the variance of the synaptic input to postsynaptic cells. It has been argued that such modulations of the noise intensity (multiplicative modulation) can be tracked much faster than modulations of the mean input current (additive modulation). Here, we compare the response characteristics of an ensemble of neocortical neurons for both modulation schemes. We injected sinusoidally modulated noisy currents (additive and multiplicative modulation) into layer V pyramidal neurons of the rat somatosensory cortex and measured the trial and ensemble-averaged spike responses for a wide range of stimulus frequencies. For both modulation paradigms, we observed low-pass behavior. The cutoff frequencies were markedly high, considerably higher than the average firing rates. We demonstrate that modulations in the variance can be tracked significantly faster than modulations in the mean input. Extremely fast stimuli (up to 1 kHz) can be reliably tracked, provided the stimulus amplitudes are sufficiently high.