Dynamic spatiotemporal synaptic integration in cortical neurons: Neuronal gain, revisited
Dynamic spatiotemporal synaptic integration in cortical neurons: Neuronal gain, revisited
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DOI：
10.1152/jn.00542.2005
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发表时间：
2005-10-01
影响因子：
2.5
通讯作者：
Azouz, R
中科院分区：
文献类型：
--
作者：
Azouz, R
增益调制是皮质神经元中普遍存在的一种现象，它提供了在不断变化的条件下运作的灵活性。普遍的观点是，这种调制反映了神经元膜特性的变化所带来的平均输入和输出放电率之间关系的变化。另一种机制提出了神经元增益调制，考虑到皮层神经元处理时空突触相关性的能力。通过数值模拟表明，电压门控和泄漏电导、膜电位、噪声和输入放电率改变了皮质神经元对其突触输入之间的时间相关程度的敏感性。这些变化表现为突触整合的时间窗口和响应概率分级的输入相关范围的变化。该研究还表明，时间积分取决于输入之间的距离，并且这种空间和时间的相互作用由电压门控和泄漏电导调制。因此，增益调制可能反映了时空突触相关性和输出放电概率之间关系的变化。进一步提出，通过与网络协同作用，皮层神经元的动态时空突触整合可能在动态细胞组装的形成中发挥功能作用。
Gain modulation is a ubiquitous phenomenon in cortical neurons, providing flexibility to operate under changing conditions. The prevailing view is that this modulation reflects a change in the relationship between mean input and output firing rate brought about by variation in neuronal membrane characteristics. An alternative mechanism is proposed for neuronal gain modulation that takes into account the capability of cortical neurons to process spatiotemporal synaptic correlations. Through the use of numerical simulations, it is shown that voltage- gated and leak conductances, membrane potential, noise, and input firing rate modify the sensitivity of cortical neurons to the degree of temporal correlation between their synaptic inputs. These changes are expressed in a change of the temporal window for synaptic integration and the range of input correlation over which response probability is graded. The study also demonstrates that temporal integration depends on the distance between the inputs and that this interplay of space and time is modulated by voltage- gated and leak conductances. Thus, gain modulation may reflect a change in the relationship between spatiotemporal synaptic correlations and output firing probability. It is further proposed that by acting synergistically with the network, dynamic spatiotemporal synaptic integration in cortical neurons may serve a functional role in the formation of dynamic cell assemblies.