A revised calcium-dependent model of theta-burst transcranial magnetic stimulation

Abstract

Calcium dependency is presently an essential assumption in modelling the neuromodulatory effects of transcranial magnetic stimulation (TMS). Among the various neuromodulatory TMS protocols, theta-burst stimulation (TBS) at present is the fastest intervention to generate strong effects. A decade ago, Y.Z. Huang et al. developed a first neuromodulation model to explain the bidirectional effects of TBS based on postsynaptic intracellular calcium concentration elevation. We discover, however, that the published computer code is not consistent with the model formulations in the corresponding paper. Further analysis confirms that the computer model with an index confusion was used for fitting the experimental results, running the simulation, and plotting the corresponding figures in the original publication. This paper intends to fix the computer code and additionally create a non-convex optimisation solution for re-calibrating the model. After re-calibration, the revised model outperforms the initial model in accuracy describing the MEP amplitudes of TBS-induced after-effects under specific situations.