Effects of Motor Imagery on Cognitive Function and Prefrontal Cortex Activity in Normal Adults Evaluated by NIRS

Abstract

Recent near-infrared spectroscopy (NIRS) studies demonstrated that physical exercise enhances working memory (WM) performance and prefrontal cortex (PFC) activity during WM tasks in normal adults. Interestingly, the effects of rehabilitation (i.e. physiotherapy) on post-stroke patients could be enhanced by motor imagery (MI), an active process during which the specified action is reproduced within WM without any actual physical movement. However, it is not known whether MI can enhance cognitive function and associated brain activity. To clarify these issues, we evaluated the effect of MI on WM performance and PFC activity during WM tasks in normal adults, employing NIRS. We studied 10 healthy adults. The present study was a crossover comparison test; the MI training and control condition (rest) were applied to the subjects at random. The Time Up and Go method was used for MI training: the subject sat on a chair and conducted MI for 3 min, three times. Neuronal activity (oxyhemoglobin concentration) in the bilateral PFC was measured using 2-CH NIRS during WM tasks. We found that MI improved the behavioral performance of WM compared with the control (p < 0.01). NIRS revealed that MI enhanced PFC activity induced by the WM task compared with the control task (p < 0.01). These results suggest that MI can improve cognitive function and increase associated PFC activity in normal adults.

Executive functions in motor imagery: support for the motor-cognitive model over the functional equivalence model

“…We suggest that these processes are identifiable with the dorsolateral prefrontal cortex (DLPFC). Concordant with this view, studies show greater activity in DLPFC during motor imagery than overt actions (Guillot et al 2009), that this tendency increases for less familiar actions (Zhang et al 2018), and that motor imagery training can increase the responsiveness of DLPFC (Moriva and Sakatani 2017). The suggested role of executive functions in motor imagery is also consistent with the putative critical role of the DLPFC in executive functions (Niendam et al 2012;Yuan and Raz 2014).…”

Physical, cognitive and psychosocial effects of telerehabilitation-based motor imagery training in people with multiple sclerosis: A randomized controlled pilot trial

“…A recent nearinfrared spectroscopy study in healthy adults suggested that MIT improves the behavioural performance of working memory and enhances prefrontal cortex activity induced by the working memory task. 38 In addition, recent studies have also suggested that MIT can improve cognitive functions in people with stroke and Parkinson's disease. 39,40 Our study has provided novel evidence on the efficacy of a Tele-MIT programme on cognitive functions in pwMS.…”

TMS Over Dorsolateral Prefrontal Cortex Affects the Timing of Motor Imagery but not Overt Action: Further Support for the Motor-Cognitive Model

“…TMS may have slightly disrupted performance in the spatial span task but did not appear to affect performance in the Go/NoGo or switching tasks. This could suggest many possibilities: Most parsimoniously, it may be that working memory is the executive function most important to motor imagery, as suggested by a study showing improvement in working memory after motor imagery training [40], and that inhibition and/or task switching are less important, or not important at all. More speculatively, it may be that motor imagery shares with all these tasks a common pool of executive resources, and that the cognitive tasks did not use enough of these executive resources to be clearly affected by TMS.…”

“…For one, numerous studies have observed a greater activation in the DLPFC during motor imagery than overt action [18,[29][30][31][32][33][34][35][36][37][38], with this activation being even greater for novel movements [34,39]. For another, motor imagery training has been shown to improve working memory through an increase in prefrontal cortical activity [40], and coupling from Supplementary Motor Area to DLPFC is critical during motor imagery [41,42], with higher connectivity at restingstate predicting greater performance [43,44].…”