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 largely 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 that 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 MI or AO independently.

Observation and imagery of movement both activate similar brain regions to those involved in movement execution. As such, both are recommended as techniques for aiding the recovery of motor function following stroke. Traditionally, action observation and movement imagery (MI) have been considered as independent intervention techniques. Researchers have however begun to consider the possibility of combining the two techniques into a single intervention strategy. This study investigated the effect of combined action observation and MI on corticospinal excitability, in comparison to either observation or imagery alone. Single-pulse transcranial magnetic stimulation (TMS) was delivered to the hand representation of the left motor cortex during combined action observation and MI, passive observation (PO), or MI of right index finger abduction-adduction movements or control conditions. Motor evoked potentials (MEPs) were recorded from the first dorsal interosseous (FDI) and abductor digiti minimi (ADM) muscles of the right hand. The combined action observation and MI condition produced MEPs of larger amplitude than were obtained during PO and control conditions. This effect was only present in the FDI muscle, indicating the facilitation of corticospinal excitability during the combined condition was specific to the muscles involved in the observed/imagined task. These findings have implications for stroke rehabilitation, where combined action observation and MI interventions may prove to be more effective than observation or imagery alone.

The movement-related cortical potential (MRCP) is a low-frequency negative shift in the electroencephalographic recording that occurs about 2 s before voluntary movement production. The MRCP is thought to reflect the cortical processes involved in movement planning and movement preparation. In recent years, researchers have used this potential to investigate the processes involved in motor skill learning. Their findings indicate differences in the amplitude and onset times of the MRCP between experienced and novice performers, which have been attributed to long-term training in the experts. The authors discuss these findings critically and consider their implications for both future research and practice.

Motor imagery (MI) and action observation (AO) are techniques that have been shown to enhance motor skill learning. While both techniques have been used independently, recent research has demonstrated that combining action observation and motor imagery (AOMI) promotes better outcomes. However, little is known about the most effective way to combine these techniques. This study examined the effects of simultaneous (i.e., observing an action whilst imagining carrying out the action concurrently) and alternate (i.e., observing an action and then doing imagery related to that action consecutively) AOMI combinations on the learning of a dart throwing task. Participants (n=50) were randomly allocated to one of five training groups: action observation (AO), motor imagery (MI), simultaneous action observation and motor imagery (S-AOMI), alternate action observation and motor imagery (A-AOMI) and a control group. Interventions were conducted three times per week for six weeks and pre-and post-measures of total score were collected. Results revealed that all intervention groups, with the exception of the AO and control groups, significantly improved performance following the intervention. Posthoc analyses showed that S-AOMI group improved to a significantly greater degree than the MI and AO groups, and participants in the A-AOMI group improved to a significantly greater degree than the AO group. Participants in the A-AOMI group did not improve to a significantly greater degree than the S-AOMI group (p =1.00). These findings suggest that combining AOMI, regardless of how it's combined, may be the beneficial method for improving the learning and performance of aiming skills.

Greg (2020) Combined action observation and motor imagery facilitates visuomotor adaptation in children with Developmental Coordination Disorder. Research in Developmental Disabilities.