The efficacy of non-invasive brain stimulation protocols for inducing neuroplasticity

Wansbrough, Kym (2016) The efficacy of non-invasive brain stimulation protocols for inducing neuroplasticity. Honours thesis, Murdoch University.

Abstract

Neuroplasticity refers to the brain’s ability to change with experience. Continuous theta burst stimulation (cTBS) is a non-invasive brain stimulation technique capable of temporarily inducing neuroplasticity in the primary motor cortex (M1), as indicated by changes in the excitability of the stimulated brain region. However, cTBS-induced neuroplasticity shows large inter-individual variability, which limits its potential in research and clinical settings. The present study investigated whether down-regulating motor cortical inhibition, with cTBS applied using a lower than conventional intensity (cTBSlow), is capable of making the brain more amenable to the neuroplasticity-inducing effects of cTBS applied using the conventional intensity. Thirty-two, right-handed, healthy adults participated in two experimental sessions: 1) cTBS primed by cTBSlow; 2) cTBS primed by sham stimulation. Due to unforeseen technical issues, there were two groups: group 1 received cTBSlow with conventional bursts; group 2 received cTBSlow with reduced pulses per burst. Motor cortical excitability and inhibition were measured from an intrinsic hand muscle at baseline, between the two cTBS applications, and following cTBS. In group 1, cTBSlow reduced inhibition in M1, however, there was no systematic change in motor cortical excitability following cTBS primed by cTBSlow or primed by sham. This lack of effect may be due to unreliable neuroplasticity induction in M1 following cTBS alone. In group 2, long-lasting and less variable changes in motor cortical excitability were found following an unconventional cTBS pattern. These findings confirm the variability of cTBS-induced neuroplasticity and highlight the importance of developing novel protocols to induce less variable neuroplasticity responses.

Item Type:	Thesis (Honours)
Murdoch Affiliation(s):	School of Psychology and Exercise Science
Supervisor(s):	Vallence, Anne-Marie and Fujiyama, Hakuei
URI:	http://researchrepository.murdoch.edu.au/id/eprint/40685

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