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Motor imagery (MI) is the capacity to mentally perform one or a set of movements without concomitant overt action. MI training has been show to enhance the subsequent motor performance. While the benefits of MI to manage stress have been extensively documented, the reverse impact of stress on MI received far less attention. The present study thus aimed to evaluate whether acute stress might influence MI abilities. Thirty participants were assigned either to a stress or a control group. The Socially Evaluated Cold Pressor Test (SECPT) was used to induce stress, with heart rate, electrodermal activity, salivary cortisol, and self-report perceived levels of stress being monitored during the experiment. Stress induction was followed by both implicit (laterality judgment) and explicit (sequential pointing) MI tasks. Main results showed a deleterious impact of stress on implicit MI, while explicit MI was not altered. These exploratory findings provide a deeper understanding of stress effects on cognition, and practically support that under stressful conditions, as during a sport competition or rehabilitation contexts, explicit MI should be prioritized.

This systematic review and meta-analysis aims to identify and quantify the current available evidence of hypnosis efficacy to manage pain in patients with chronic musculoskeletal and neuropathic pain. Randomized Control Trials (RCTs) with hypnosis and/or self-hypnosis treatment used to manage musculoskeletal and/or neuropathic chronic pain in adults and assessing pain intensity were included. Reviews, meta-analyses, non-randomized clinical trials, case reports and meeting abstracts were excluded. Five databases, up until May 13th 2021, were used to search for RCTs using hypnosis to manage chronic musculoskeletal and/or neuropathic pain. The protocol is registered on PROSPERO register (CRD42020180298) and no specific funding was received for this review. The risk of bias asessement was conducted according to the revised Cochrane risk of bias tool for randomized control trials (RoB 2.0). Nine eligible RCTs including a total of 530 participants were considered. The main analyses showed a moderate decrease in pain intensity (Hedge's g: -0.42; p = 0.025 after intervention, Hedge's g: -0.37; p = 0.027 after short-term follow-up) and pain interference (Hedge's g: -0.39; p = 0.029) following hypnosis compared to control interventions. A significant moderate to large effect size of hypnosis compared to controls was found for at 8 sessions or more (Hedge's g: -0.555; p = 0.034), compared to a small and not statistically significant effect for fewer than 8 sessions (Hedge's g: -0.299; p = 0.19). These findings suggest that a hypnosis treatment lasting a minimum of 8 sessions could offer an effective complementary approach to manage chronic musculoskeletal and neuropathic pain. Future research is needed to delineate the relevance of hypnosis in practice and its most efficient prescription.

Anticipating a stressful situation involves psychophysiological reactions before the occurrence of the overt stress event. The current challenge in the stress domain is to characterize anticipatory stress reactions and how to effectively modulate them. The present study aimed to characterize the anticipation period and evaluate the benefits of a heart-rate variability biofeedback (BFB) intervention designed to manage anticipatory stress. Healthy participants were exposed to an anticipation stress period (15 min) during which they either practised BFB ( stress + bfb, n = 15) or watched a neutral video ( stress + video, n = 14). Anticipatory stress was effectively induced by the Trier Social Anticipatory Stress (TSAS) protocol, specifically designed for this study. Control participants, without anticipation stress, practised BFB for an equivalent time ( ctrl + bfb, n = 15). Subsequently, all participants performed a set of cognitive tasks assessing executive functions. Heart-rate variability (cardiac coherence, standard deviation of the R–R intervals, root mean square of successive difference measure) and the evolution of the perceived psychological state were measured during the anticipation period. Self-reported judgements of how the intervention influenced stress and performance were further assessed. The main result showed that BFB is a relevant proactive stress-coping method. Compared with the stress + video group, participants who practised BFB attained higher cardiac coherence scores. Post-intervention self-reported measures revealed that BFB contributed to reduce psychological stress and increase perceived levels of performance. Together, these findings provide practical guidelines for examining the stress anticipation period by means of the TSAS protocol.

Background Acquisition and consolidation of a new motor skill occurs gradually over long time span. Motor imagery (MI) and brain stimulation have been showed as beneficial approaches that boost motor learning, but little is known about the extent of their combined effects. Objective Here, we aimed to investigate, for the first time, whether delivering multiple sessions of transcranial direct current stimulation (tDCS) over primary motor cortex during physical and MI practice might improve implicit motor sequence learning in a young population. Methods Participants practiced a serial reaction time task (SRTT) either physically or through MI, and concomitantly received either an anodal (excitatory) or sham stimulation over the primary motor cortex during three successive days. The effect of anodal tDCS on the general motor skill and sequence specific learning were assessed on both acquisition (within-day) and consolidation (between-day) processes. We further compared the magnitude of motor learning reached after a single and three daily sessions of tDCS. Results The main finding showed that anodal tDCS boosted MI practice, but not physical practice, during the first acquisition session. A second major result showed that compared to sham stimulation, multiple daily session of anodal tDCS, for both types of practice, resulted in greater implicit motor sequence learning rather than a single session of stimulation. Conclusions The present study is of particular importance in the context of rehabilitation, where we postulate that scheduling mental training when patients are not able to perform physical movement might beneficiate from concomitant and consecutive brain stimulation sessions over M1 to promote functional recovery.