Synaptic reshaping of plastic neuronal networks by periodic multichannel stimulation with single-pulse and burst stimuli

Synaptic dysfunction is associated with several brain disorders, e.g., Parkinson's disease. Utilizing synaptic plasticity, brain stimulation is capable of reshaping synaptic connectivity. Novel stimulation techniques that counteract pathological synaptic connectivity may induce long-lasting therapeutic effects. We study synaptic reshaping by periodic multichannel stimulation (PMCS). During PMCS, phase-shifted stimuli are delivered to segregated neuronal subpopulations. Harnessing STDP, PMCS changes the synaptic network structure. We compare theoretical approximations of the stimulation-induced network structure to simulations of PMCS of networks of leaky integrate-and-fire neurons with spike-timing-dependent plasticity. PMCS-induced synaptic reshaping depends on the phase lags between stimuli and the stimulus type. Single-pulse stimuli and burst stimuli with low intraburst frequency down-regulate, whereas burst stimuli with high intraburst frequency up-regulate synaptic connections between simultaneously stimulated neurons. Our results may impact parameter adjustment procedures for clinical deep brain stimulation (DBS), which, so far, focus on acute effects. They further provide testable hypotheses on the effect of the stimulus type on the long-lasting outcome of DBS.