F.J. Veredas and H. Mesa (Spain)
Integrate-and-fire neuron, synaptic conductance, correlated activity, Z-transformation.
Across the visual pathway strong monosynaptic connec tions generate precise correlated activity between presy naptic and postsynaptic neurons. The degree of this precise correlated activity can be inferred from the monosynap tic cross-correlogram peak-width. Retinogeniculate con nections generate correlograms with very narrow peaks, while geniculocortical or corticocortical peaks are wider. While it is difficult to determine the physiological parame ters that contribute to the precision of the correlated firing in physiological experiments, a first approach can be done by computational modeling and simulation. In this article we present a new integrate-and-fire(IAF) neuron model de signed and computationally optimized to analyse the con tribution of the main physiological factors to the correlated activity. Our results suggest that the precision of the corre lated firing generated by strong monosynaptic connections is mostly determined by the EPSP time course of the con nection and much less by other factors. The model stands out to incorporate the modulation of the synaptic conduc tance based on two alpha functions with different time constants to independently analyse the influence of the rise and decay times of the conductance on the correlated activ ity. A Z-transformation of the synaptic conductance equa tion turns it into a recursive function that significantly in creases the computational efficiency of the IAF model.
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