Temporal integration by calcium dynamics in a model neuron
Temporal integration by calcium dynamics in a model neuron
复制标题
DOI：
10.1038/nn1109
复制
发表时间：
2003-09-01
影响因子：
25
通讯作者：
Sompolinsky, H
中科院分区：
文献类型：
--
作者：
Loewenstein, Y;Sompolinsky, H
通过速度信号的时间积分来计算和存储位置变量对于姿势、前庭眼反射（VOR）和导航是必不可少的。积分神经元以多种速率表现出持续放电，这些速率代表记忆的位置变量的值。一个普遍的假设是，时间整合是递归网络中反馈回路的结果，但这一假设尚未得到实验证明。在这里，我们提出了一个单细胞模型的神经积分。钙的非线性动力学引起钙波阵面沿着树枝状过程传播。波前速度由突触输入调制，使得前位置与其先前输入的时间和协变。钙依赖性电流将此信息转换为伴随的持续放电。因此，单个神经元中的钙动力学可能是模拟记忆任务期间在神经元中观察到的分级持续活动和时间整合的生理基础。
The calculation and memory of position variables by temporal integration of velocity signals is essential for posture, the vestibulo-ocular reflex (VOR) and navigation. Integrator neurons exhibit persistent firing at multiple rates, which represent the values of memorized position variables. A widespread hypothesis is that temporal integration is the outcome of reverberating feedback loops within recurrent networks, but this hypothesis has not been proven experimentally. Here we present a single-cell model of a neural integrator. The nonlinear dynamics of calcium gives rise to propagating calcium wave-fronts along dendritic processes. The wave-front velocity is modulated by synaptic inputs such that the front location covaries with the temporal sum of its previous inputs. Calcium-dependent currents convert this information into concomitant persistent firing. Calcium dynamics in single neurons could thus be the physiological basis of the graded persistent activity and temporal integration observed in neurons during analog memory tasks.