OBJECTIVE: Theta burst stimulation, a form of repetitive transcranial magnetic stimulation, can induce lasting changes in corticospinal excitability that are thought to involve long-term potentiation/depression (LTD/LTD)-like effects on cortical synapses. The pattern of delivery of TBS is crucial in determining the direction of change in synaptic efficiency. Previously we explained this by postulating (1) that a single burst of stimulation induces a mixture of excitatory and inhibitory effects and (2) those effects may cascade to produce long-lasting effects. Here we formalise those ideas into a simple mathematical model. METHODS: The model is based on a simplified description of the glutamatergic synapse in which post-synaptic Ca(2+) entry initiates processes leading to different amount of potentiation and depression of synaptic transmission. The final effect on the synapse results from summation of the two effects. RESULTS: The model using these assumptions can fit reported data. Metaplastic effects of voluntary contraction on the response to TBS can be incorporated by changing time constants in the model. CONCLUSIONS: The pattern-dependent after-effects and interactions with voluntary contraction can be successfully modelled by using reasonable assumptions about known cellular mechanisms of plasticity. SIGNIFICANCE: The model could provide insight into development of new plasticity induction protocols using TMS.
OBJECTIVE: Theta burst stimulation, a form of repetitive transcranial magnetic stimulation, can induce lasting changes in corticospinal excitability that are thought to involve long-term potentiation/depression (LTD/LTD)-like effects on cortical synapses. The pattern of delivery of TBS is crucial in determining the direction of change in synaptic efficiency. Previously we explained this by postulating (1) that a single burst of stimulation induces a mixture of excitatory and inhibitory effects and (2) those effects may cascade to produce long-lasting effects. Here we formalise those ideas into a simple mathematical model. METHODS: The model is based on a simplified description of the glutamatergic synapse in which post-synaptic Ca(2+) entry initiates processes leading to different amount of potentiation and depression of synaptic transmission. The final effect on the synapse results from summation of the two effects. RESULTS: The model using these assumptions can fit reported data. Metaplastic effects of voluntary contraction on the response to TBS can be incorporated by changing time constants in the model. CONCLUSIONS: The pattern-dependent after-effects and interactions with voluntary contraction can be successfully modelled by using reasonable assumptions about known cellular mechanisms of plasticity. SIGNIFICANCE: The model could provide insight into development of new plasticity induction protocols using TMS.
Authors: Ying-Zu Huang; Martin Sommer; Gary Thickbroom; Masashi Hamada; Alvero Pascual-Leonne; Walter Paulus; Joseph Classen; Angel V Peterchev; Abraham Zangen; Yoshikazu Ugawa Journal: Brain Stimul Date: 2008-10-07 Impact factor: 8.955
Authors: V Di Lazzaro; F Pilato; M Dileone; P Profice; A Oliviero; P Mazzone; A Insola; F Ranieri; M Meglio; P A Tonali; J C Rothwell Journal: J Physiol Date: 2008-06-19 Impact factor: 5.182
Authors: Giovanni Di Pino; Giovanni Pellegrino; Giovanni Assenza; Fioravante Capone; Florinda Ferreri; Domenico Formica; Federico Ranieri; Mario Tombini; Ulf Ziemann; John C Rothwell; Vincenzo Di Lazzaro Journal: Nat Rev Neurol Date: 2014-09-09 Impact factor: 42.937
Authors: Lysianne Beynel; Lawrence G Appelbaum; Bruce Luber; Courtney A Crowell; Susan A Hilbig; Wesley Lim; Duy Nguyen; Nicolas A Chrapliwy; Simon W Davis; Roberto Cabeza; Sarah H Lisanby; Zhi-De Deng Journal: Neurosci Biobehav Rev Date: 2019-08-29 Impact factor: 8.989