The effect of manipulating action observation variables on corticospinal excitability using transcranial magnetic stimulation

Riach, Martin (2018) The effect of manipulating action observation variables on corticospinal excitability using transcranial magnetic stimulation. Doctoral thesis (PhD), Manchester Metropolitan University.

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Abstract

Action observation interventions have been shown to contribute to improvements in motor performance and (re)learning. This thesis examined the effect of manipulating action observation variables on corticospinal excitability (CSE) using transcranial magnetic stimulation (TMS), with the aim of informing interventions for motor (re)learning. Eye-tracking and interview techniques were employed in combination with TMS to provide novel explorations for how screen position, visual context, and emotional valence influence CSE, visual attention, and individual experience during action observation. The Pilot Experiment (Chapter 5) tested the appropriateness of both single- and paired-pulse TMS techniques during action observation. Results determined that single-pulse TMS was appropriate for the subsequent experiments included in this thesis. Experiment 1 (Chapter 6) investigated the effect of screen position during action observation on CSE. The results demonstrated greater CSE during action observation on a horizontal, compared to a vertical, screen position, but only once each individual’s viewing preference had been taken into account. Experiment 2 (Chapter 7) investigated the effect of congruent and incongruent contexts on CSE. The results indicated that congruent context during action observation facilitates CSE more than control conditions in contrast to an incongruent visual context. Experiment 3 (Chapter 8) explored the effect of each participant’s most preferred, least preferred, and neutral preference food items involved in an observed reach and grasp action on CSE. The results showed no significant differences between the control condition and observing a reach and grasp of each participant’s personalised least preferred and neutral preference food items. Significant inhibition of CSE was shown during observation of a reach and grasp of each participant’s most preferred food item. The three main experiments in this thesis provide novel contributions to action observation literature by incorporating eye-tracking and interview techniques in combination with TMS to better determine the nature of CSE modulation. Taken together, these findings directly inform both future research and practice in motor (re)learning by highlighting the importance of meaning and context during action observation.