A neural signature for combined action observation and motor imagery? An fNIRS study into prefrontal activation, automatic imitation, and self-other perceptions

Transformation but not generation of motor images is disrupted following stimulation over the left inferior parietal lobe

Motor imagery (MI) involves the generation, maintenance, and transformation of motor images; yet, the neural underpinnings of each stage are not well understood. Here, we investigated the role of the left inferior parietal lobe (IPL) in the stages of MI. Healthy participants (N = 20) engaged in a MI task (making judgments about hands presented on a screen; hand laterality judgment task) over two days. Past literature demonstrates the mental rotation of hands in this task involves implicit MI (i.e., where MI occurs spontaneously in the absence of explicit instructions). During the task, active (Day A; 120% resting motor threshold) or sham (Day B; placebo) neuronavigated transcranial magnetic stimulation (TMS) was applied to the left IPL (location determined from past neuroimaging work) on 50% of trials at 250, 500, or 750ms post-stimulus onset, corresponding to different stages of MI. A/B days were randomized across participants. Linear mixed effects (LME) modelling conducted on reaction time and accuracy revealed that longer reaction times were observed when TMS was delivered at 750ms after trial onset, and more greatly for active vs. sham stimulation. This effect was exacerbated for palm-vs. back-view stimuli and for left vs. right hands. Accuracy overall was decreased for active vs. sham stimulation, and to a greater extent for palm-vs. back-view stimuli. Findings suggest that the left IPL is involved in image transformation. Overall this work informs on the neural underpinnings of the stages of MI.

Understanding effects of observing affordance-driven action during motor imagery through EEG analysis

The aim of this paper is to investigate the impact of observing affordance-driven action during motor imagery. Affordance-driven action refers to actions that are initiated based on the properties of objects and the possibilities they offer for interaction. Action observation (AO) and motor imagery (MI) are two forms of motor simulation that can influence motor responses. We examined combined AO + MI, where participants simultaneously engaged in AO and MI. Two different kinds of combined AO + MI were employed. Participants imagined and observed the same affordance-driven action during congruent AO + MI, whereas in incongruent AO + MI, participants imagined the actual affordance-driven action while observing a distracting affordance involving the same object. EEG data were analyzed for the N2 component of event-related potential (ERP). Our study found that the N2 ERP became more negative during congruent AO + MI, indicating strong affordance-related activity. The maximum source current density (0.00611 μ A/mm2 ) using Low-Resolution Electromagnetic Tomography (LORETA) was observed during congruent AO + MI in brain areas responsible for planning motoric actions. This is consistent with prefrontal cortex and premotor cortex activity for AO + MI reported in the literature. The stronger neural activity observed during congruent AO + MI suggests that affordance-driven actions hold promise for neurorehabilitation.

A commentary on Eaves et al. with a special focus on clinical neurorehabilitation

We very much appreciate the theoretical foundations and considerations of AO, MI, and their combination AO + MI by Eaves et al. In their exploratory review, the authors highlight the beneficial effects of the combined use of AO and MI, with a particular focus on synchronous AO and MI. From a neurorehabilitation perspective, different processes may apply to patients, particularly after a stroke. As suggested by Eaves et al., the cognitive load might prevent the use of synchronous AO + MI and the asynchronous application of AO and MI might be indicated. Furthermore, some aspects should be considered when applying AO + MI in rehabilitation: screening for the patients' cognitive capabilities and MI ability, and a familiarisation programme for AO and MI, before starting with an AO + MI training. With their review, Eaves et al. propose a number of research questions in the field of neurorehabilitation that urgently need to be addressed: the use of asynchronous vs. synchronous AOMI, observation and imagination with or without errors, or use of different MI perspectives and modes in different learning stages. This commentary provides some additional suggestions on patients' MI ability and cognitive level, MI familiarisation and detailed reporting recommendations to transfer Eaves et al. findings into clinical practice.

Development and Validation of the Combined Action Observation and Motor Imagery Ability Questionnaire

Combined use of action observation and motor imagery (AOMI) is an increasingly popular motor-simulation intervention, which involves observing movements on video while simultaneously imagining the feeling of movement execution. Measuring and reporting participant imagery-ability characteristics are essential in motor-simulation research, but no measure of AOMI ability currently exists. Accordingly, the AOMI Ability Questionnaire (AOMI-AQ) was developed to address this gap in the literature. In Study 1, two hundred eleven participants completed the AOMI-AQ and the kinesthetic imagery subscales of the Movement Imagery Questionnaire-3 and Vividness of Motor Imagery Questionnaire-2. Following exploratory factor analysis, an 8-item AOMI-AQ was found to correlate positively with existing motor-imagery measures. In Study 2, one hundred seventy-four participants completed the AOMI-AQ for a second time after a period of 7-10 days. Results indicate a good test-retest reliability for the AOMI-AQ. The new AOMI-AQ measure provides a valid and reliable tool for researchers and practitioners wishing to assess AOMI ability.

The Positive Impact of Combining Motor Imagery, Action Observation and Coach's Feedback on Archery Accuracy of Young Athletes

In recent years, learning and motor control researchers have examined, in diverse ways, the practical strategies that enhance motor skill acquisition in sport. In this study we investigated the impact of combining Motor Imagery (MI), Feedback (F), and Action Observation (AO) on the quality of archery longbow shooting at a 10-meter target. We randomly assigned 60 young athletes to (a) a Control group (Control), (b) a Feedback and Motor Imagery group (F + MI), and (c) a Feedback, Motor Imagery, and Action Observation group (F + MI + AO). Over an 8-week intervention period athletes performed two training sessions per week. During each session, all participants engaged in two blocks of ten effective shots. Performance improvement was significantly greater in the F + MI + AO group than in the two other groups, confirming the beneficial impact of combining all three methods of improving archery accuracy. These findings suggest practical recommendations for athletes and trainers for delivering optimal mental training to improve shooting accuracy for these archers.

Motor learning without physical practice: The effects of combined action observation and motor imagery practice on cup-stacking speed

In this study we explored training effects for combined action observation and motor imagery (AO + MI) instructions on a complex cup-stacking task, without physical practice. Using a Graeco-Latin Square design, we randomly assigned twenty-six participants into four groups. This counterbalanced the within-participant factor of practice condition (AO + MI, AO, MI, Control) across four cup-stacking tasks, which varied in their complexity. On each of the three consecutive practice days participants experienced twenty trials under each of the three mental practice conditions. On each trial, a first-person perspective video depicted bilateral cup-stacking performed by an experienced model. During AO, participants passively observed this action, responding only to occasional colour cues. For AO + MI, participants imagined performing the observed action and synchronised their concurrent MI with the display. For MI, a sequence of pictures cued imagery of each stage of the task. Analyses revealed a significant main effect of practice condition both at the 'surprise' post-test (Day 3) and at the one-week retention test. At both time points movement execution times were significantly shorter for AO + MI compared with AO, MI and the Control. Execution times were also shorter overall at the retention compared with the post-test. These results demonstrate that a complex novel motor task can be acquired without physical training. Practitioners can therefore use AO + MI practice to supplement physical practice and optimise skill learning.

Combinations of action observation and motor imagery on golf putting's performance

Motor imagery (MI) and action observation (AO) have been found to enhance motor performance, but recent research found that a combination of action observation and motor imagery (AOMI) together is even better. Despite this initial finding, the most effective way to combine them is unknown. The present study examined the effects of synchronized (i e., concurrently doing AO and MI), asynchronised (i.e., first doing AO then MI), and progressive (first asynchronised approach, then doing synchronized approach) AOMI on golf putting performance and learning. We recruited 45 university students (Mage = 20.18 + 1.32 years; males = 23, females = 22) and randomly assigned them into the following four groups: synchronized group (S-AOMI), asynchronised group (A-AOMI), progressive group (A-S-AOMI), and a control group with a pre-post research design. Participants engaged in a 6-week (three times/per-week) intervention, plus two retention tests. A two-way (group × time) mixed ANOVA statistical analysis found that the three experimental groups performed better than the control group after intervention. However, we found progressive and asynchronised had better golf putting scores than synchronized group and the control group on the retention tests. Our results advance knowledge in AOMI research, but it needs more research to reveal the best way of combining AOMI in the future. Theoretical implications, limitations, applications, and future suggestions are also discussed.