The effect of acute itch on the motor evoked potential : an investigation using transcranial magnetic brain stimulation

Page, Matthew Lewis

Abstract

research into the functioning of the brain during itch has revealed significant activity in the motor cortex, however, the role of the motor cortex during itch is not completely known. It is theorised to be involved in the planning of scratching movement. Two studies compared the effect of histamine induced itch and placebo on motor evoked potentials, elicited from navigated transcranial magnetic stimulation from the first dorsal interossei muscle. Study 1 investigated cortical changes in the contralateral motor cortex. Study 2 investigated the ipsilateral motor cortex. For both studies, neurotypical participants had to do a simple visual attention task whilst receiving pulses. Motor evoked potentials were recorded from 16 neurotypical participants in study 1, then baseline corrected peak-to-peak amplitudes were analysed across conditions. There was a significant increase in baseline corrected amplitudes for the histamine condition compared to the placebo within the contralateral motor cortex. Furthermore, analysis showed significant amplitude increases 5 to 8 minutes post prick, compared to the first 1 to 4 minutes across conditions. For Study 2, 14 participants’ data was analysed. There was only a significant difference between halves, with the last 5-to-8-minute half showing significantly higher amplitudes than the first. It was concluded histamine itch sensations tend to elicit higher levels of excitability, especially in the contralateral motor cortex. However, the arousal from the attention task may have also facilitated this increase in excitability.

Citation

Page, M. L. The effect of acute itch on the motor evoked potential : an investigation using transcranial magnetic brain stimulation. (Thesis). University of Hull. https://hull-repository.worktribe.com/output/4270500

• Thesis Type: Thesis
• Deposit Date: Apr 27, 2023
• Publicly Available Date: Apr 27, 2023
• Keywords: Psychology
• Public URL: https://hull-repository.worktribe.com/output/4270500
• Additional Information: Department of Psychology, The University of Hull
• Award Date: 2022-09