Combined effects of STDP and homeostatic structural plasticity on coherence resonanceEfficient processing and transfer of information in neurons have been linked
to noise-induced resonance phenomena such as coherence resonance (CR), and
adaptive rules in neural networks have been mostly linked to two prevalent
mechanisms: spike-timing-dependent plasticity (STDP) and homeostatic structural
plasticity (HSP). Thus, this paper investigates CR in small-world and random
adaptive networks of Hodgkin-Huxley neurons driven by STDP and HSP. Our
numerical study indicates that the degree of CR strongly depends, and in
different ways, on the adjusting rate parameter $P$, which controls STDP, on
the characteristic rewiring frequency parameter $F$, which controls HSP, and on
the parameters of the network topology. In particular, we found two robust
behaviors: (i) Decreasing $P$ (which enhances the weakening effect of STDP on
synaptic weights) and decreasing $F$ (which slows down the swapping rate of
synapses between neurons) always leads to higher degrees of CR in small-world
and random networks, provided that the synaptic time delay parameter $τ_c$
has some appropriate values. (ii) Increasing the synaptic time delay $τ_c$
induces multiple CR (MCR) -- the occurrence of multiple peaks in the degree of
coherence as $τ_c$ changes -- in small-world and random networks, with MCR
becoming more pronounced at smaller values of $P$ and $F$. Our results imply
that STDP and HSP can jointly play an essential role in enhancing the time
precision of firing necessary for optimal information processing and transfer
in neural systems and could thus have applications in designing networks of
noisy artificial neural circuits engineered to use CR to optimize information
processing and transfer.
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