Thesis
Improving interhemispheric inhibition (IHI) in healthy human adults via dual-site transcranial alternating current stimulation (ds-tACS)
Honours, Murdoch University
2022
Abstract
Transcranial Alternating Current Stimulation (tACS) is a relatively new form of non-invasive brain stimulation technique known to improve motor performance in healthy and clinical populations. In particular, concurrent stimulation of distant cortical regions via tACS appeared to be effective in improving motor performance through enhancing functional communication between regions. However, the mechanisms underlying this improvement in the primary motor cortex (M1) specifically, are currently not well defined. The current study aims to experimentally investigate the effect of tACS on interhemispheric inhibition (IHI), a key mechanism in successful motor function, including manual dexterity, hypothesised to improve following tACS. Healthy right-handed human adults (N = 18, 16-62 years) received oscillatory phase-matched 20Hz dual-site (ds) tACS for 20 minutes at rest, to discover whether improvements in functional connectivity enhance motor performance. Before and after the application of ds-tACS, IHI and manual dexterity were assessed using transcranial magnetic stimulation (TMS) and a perdue pegboard test respectively. Results indicated a specific IHI circuit that involved indirect connections between M1s increased following ds-tACS (p = .04, d = -0.88), which was accompanied by an improvement in manual dexterity performance (p < .001, d = 1.37), this pattern was absent in the sham session. The present study suggested that ds-tACS improves functional connectivity between the M1s, which likely encouraged bimanual dexterity. The results provide substantial insight into the neurophysiological foundations of ds-tACS induced improvement in motor performance and functioning, which has contributed to groundwork for future intervention programs for clinical populations, such as stroke patients.
Details
- Title
- Improving interhemispheric inhibition (IHI) in healthy human adults via dual-site transcranial alternating current stimulation (ds-tACS)
- Authors/Creators
- Natasia Leclercq
- Contributors
- Hakuei Fujiyama (Supervisor) - Murdoch University, Centre for Healthy Ageing
- Awarding Institution
- Murdoch University; Honours
- Identifiers
- 991005582070307891
- Murdoch Affiliation
- School of Psychology
- Resource Type
- Thesis
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