Figure 4.
Constructive effect of independent random input on the synaptic weights and self-organized noise resistance of the ensemble of Hodgkin–Huxley neurons (113, 114) with STDP. (A) Time courses of the mean synaptic weight C(t) for different intensities of the random stimulation as indicated in the legend, where each neuron receives an independent random excitatory synaptic input. The initial synaptic weights cij(0) are randomly Gaussian distributed around the mean value C0 = 0.5 with SD 0.02. (B) Mean synaptic weight C(t) (scale on the left vertical axis) and the time-averaged order parameters <RSTDP> and <RFix> (scale on the right vertical axis) for the ensemble with and without STDP, respectively, versus input intensity K. For the network without STDP, the coupling matrix is fixed as for the stimulation-free case (see plot C for K = 0). (C) Coupling matrices established in the neuronal ensemble due to STDP for the input intensities indicated in the plots. For illustration, the neurons are sorted with respect to increasing natural spiking frequency. The plots are adapted from Ref. (129), where further details can be found.