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

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

Taking stock: a visual analysis of gendered ageing

While various forms of imagery have been highlighted as central to processes of social construction, the potential of visual methodologies to generate insight into gendered ageing has yet to be fully exploited. We build on the developing body of visual analyses within work and organization studies to suggest how understandings of gendered ageing are impacted by our consumption of work-related images, empirically explored here using stock photographs. We examine images of men and women of various ages to unpack the visual construction of gendered ageing within online news media, a critical context within the new economy. Through our own analysis, and our review of participants’ responses to three images, we contribute to the unpacking of culturally produced age-sensitive subject positions through examination of the interrelationships between gender, age and employment. These combined methodologies offer new insights into ways in which understandings of gendered ageing are both (visually) constructed and interpreted

The need for fresh blood: understanding organizational age inequality through a vampiric lens

YesThis article argues that older age inequality within and across working life is the result of vampiric forms and structures constitutive of contemporary organizing. Rather than assuming ageism occurs against a backdrop of neutral organizational processes and practices, the article denaturalizes (and in the process super-naturalizes) organizational orientations of ageing through three vampiric aspects: (un)dying, regeneration and neophilia. These dimensions are used to illustrate how workplace narratives and logics normalize and perpetuate the systematic denigration of the ageing organizational subject. Through our analysis it is argued that older workers are positioned as inevitable ‘sacrificial objects’ of the all-consuming immortal organization. To challenge this, the article explicitly draws on the vampire and the vampiric in literature and popular culture to consider the possibility of subverting existing notions of the ‘older worker’ in order to confront and challenge the subtle and persistent monstrous discourses that shape organizational life

Screen Position Preference Offers a New Direction for Action Observation Research: Preliminary Findings Using TMS

Action observation has been suggested to be an effective adjunct to physical practice in motor (re)learning settings. However, optimal viewing conditions for interventions are yet to be established. Single-pulse transcranial magnetic stimulation (TMS) was used to investigate the effect of two different screen positions and participants’ screen position viewing preference on the amplitude of motor evoked potentials (MEPs) during observation of a ball pinch action. Twenty-four participants observed four blocked conditions that contained either a dynamic index finger-thumb ball pinch or a static hand holding a ball in a similar position on a horizontally or vertically positioned screen. TMS was delivered to the hand representation of the left primary motor cortex and MEPs were recorded from the first dorsal interosseous muscle of the right hand. Initial analysis of the normalized MEP amplitude data showed no significant differences between conditions. In a follow-up procedure, participants engaged in individual semi-structured interviews and completed a questionnaire designed to assess viewing affect and screen position viewing preference. The MEP data were subsequently split by screen position preference and re-analyzed using a 2 × 2 repeated measures ANOVA. Main effects indicated that participants who preferred the horizontal screen position (n = 16) demonstrated significantly greater MEP amplitudes during observation of the ball-pinch action compared to the static hand condition irrespective of screen position, and during the horizontal compared to the vertical screen position irrespective of video type. These results suggest that ensuring anatomical and perceptual congruency with the physical task, alongside consideration of participants’ screen position viewing preferences, may be an important part of optimizing action observation interventions

Motor imagery during action observation: A brief review of evidence, theory and future research opportunities

Motor imagery (MI) and action observation (AO) have traditionally been viewed as two separate techniques, which can both be used alongside physical practice to enhance motor learning and rehabilitation. Their independent use has been shown to be effective, and there is clear evidence that the two processes can elicit similar activity in the motor system. Building on these well-established findings, research has now turned to investigate the effects of their combined use. In this article, we first review the available neurophysiological and behavioral evidence for the effects of combined action observation and motor imagery (‘AO+MI’) on motor processes. We next describe a conceptual framework for their combined use, and then discuss several areas for future research into AO+MI processes. In this review, we advocate a more integrated approach to AO+MI techniques than has previously been adopted by movement scientists and practitioners alike. We hope this early review of an emergent body of research, along with a related set of research questions, can inspire new work in this area. We are optimistic that future research will further confirm if, how, and when this combined approach to AO+MI can be more effective in motor learning and rehabilitation settings, relative to the more traditional application of AO or MI independently

Directing visual attention during action observation modulates corticospinal excitability

Transcranial magnetic stimulation (TMS) research has shown that corticospinal excitability is facilitated during the observation of human movement. However, the relationship between corticospinal excitability and participants’ visual attention during action observation is rarely considered. Nineteen participants took part in four conditions: (i) a static hand condition, involving observation of a right hand holding a ball between the thumb and index finger; (ii) a free observation condition, involving observation of the ball being pinched between thumb and index finger; and (iii and iv) finger-focused and ball-focused conditions, involving observation of the same ball pinch action with instructions to focus visual attention on either the index finger or the ball. Single-pulse TMS was delivered to the left motor cortex and motor evoked potentials (MEPs) were recorded from the first dorsal interosseous (FDI) and abductor digiti minimi muscles of the right hand. Eye movements were recorded simultaneously throughout each condition. The ball-focused condition produced MEPs of significantly larger amplitude in the FDI muscle, compared to the free observation or static hand conditions. Furthermore, regression analysis indicated that the number of fixations on the ball was a significant predictor of MEP amplitude in the ball-focused condition. These results have important implications for the design and delivery of action observation interventions in motor (re)learning settings. Specifically, providing viewing instructions that direct participants to focus visual attention on task-relevant objects affected by the observed movement promotes activity in the motor system in a more optimal manner than free observation or no instructions

Mean MEP amplitudes from the FDI and ADM muscles, displayed as z-scores, for the static hand, free observation, finger-focused and ball-focused conditions.

<p>Positive z-score values indicate that the MEP amplitude in that condition was greater than the mean MEP amplitude in that muscle across all conditions. Negative z-score values indicate that the MEP amplitude in that condition was less than the mean MEP amplitude in that muscle across all conditions.</p

Total number of fixations made in each area of interest for the static hand, free observation, finger-focused and ball-focused conditions.

<p>Total number of fixations made in each area of interest for the static hand, free observation, finger-focused and ball-focused conditions.</p

Mean raw MEP amplitude values (± SE) from the FDI and ADM muscles for the static hand, free observation, finger-focused and ball-focused conditions.

<p>Mean raw MEP amplitude values (± SE) from the FDI and ADM muscles for the static hand, free observation, finger-focused and ball-focused conditions.</p