title: Spike Pattern Structure Influences Synaptic Efficacy Variability under STDP and Synaptic Homeostasis. II: Spike Shuffling Methods on LIF Networks.
abstract: Synapses may undergo variable changes during plasticity because of the variability of spike patterns such as temporal stochasticity and spatial randomness. Here, we call the variability of synaptic weight changes during plasticity to be efficacy variability. In this paper, we investigate how four aspects of spike pattern statistics (i.e., synchronous firing, burstiness/regularity, heterogeneity of rates and heterogeneity of cross-correlations) influence the efficacy variability under pair-wise additive spike-timing dependent plasticity (STDP) and synaptic homeostasis (the mean strength of plastic synapses into a neuron is bounded), by implementing spike shuffling methods onto spike patterns self-organized by a network of excitatory and inhibitory leaky integrate-and-fire (LIF) neurons. With the increase of the decay time scale of the inhibitory synaptic currents, the LIF network undergoes a transition from asynchronous state to weak synchronous state and then to synchronous bursting state. We first shuffle these spike patterns using a variety of methods, each designed to evidently change a specific pattern statistics; and then investigate the change of efficacy variability of the synapses under STDP and synaptic homeostasis, when the neurons in the network fire according to the spike patterns before and after being treated by a shuffling method. In this way, we can understand how the change of pattern statistics may cause the change of efficacy variability. Our results are consistent with those of our previous study which implements spike-generating models on converging motifs. We also find that burstiness/regularity is important to determine the efficacy variability under asynchronous states, while heterogeneity of cross-correlations is the main factor to cause efficacy variability when the network moves into synchronous bursting states (the states observed in epilepsy).
authors.affiliation: State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of SciencesBeijing, China; Department of Physics, Hong Kong Baptist UniversityKowloon Tong, Hong Kong.
authors.forename: Zedong
authors.initials: Z
authors.lastname: Bi
authors.affiliation: Department of Physics, Hong Kong Baptist UniversityKowloon Tong, Hong Kong; Centre for Nonlinear Studies, Beijing-Hong Kong-Singapore Joint Centre for Nonlinear and Complex Systems, Institute of Computational and Theoretical Studies, Hong Kong Baptist UniversityKowloon Tong, Hong Kong; Beijing Computational Science Research CenterBeijing, China; Research Centre, Hong Kong Baptist University Institute of Research and Continuing EducationShenzhen, China.
authors.forename: Changsong
authors.initials: C
authors.lastname: Zhou
keywords: STDP; efficacy variability; spike pattern structure; spike shuffling methods; synaptic homeostasis; synaptic plasticity