The higher the basal vagal tone the better the motor imagery ability

Purpose: A positive association between resting state vagal tone and performance of a few cognitive functions has been proposed. Aim of this study was to investigate the possible association between vagal tone and motor imagery (MI), as MI is based on high-level cognitive processes such as attention, working memory and inhibitory control. Methods: The experiment consisted of the execution of a motor sequence and of the MI of the same action in the kinesthetic and internal visual modality. Participants with high (High, N=15) and low (Low, N=16) vagal tone at rest, were characterized for imagery and executive functions abilities through the Motor imagery questionnaire and standard cognitive tests (Trail Making test A and B, Digit span and Corsi test). We studied as indices of vagal tone a few variables estimated from heart rate variability: the sroot mean square of successive heart-beat-intervals differences (RMSSD), the high frequency band (HF), the standard deviation 1 of Poincare plot (SD1). As indices of MI ability we measured the isochrony between real and imagined movements and the reported vividness of imagery. Results: A significantly greater isochrony was observed in Highs than in Lows only for the kinesthetic modality of imagery. Isochrony was not predicted by trait imagery abilities and did not correlate with vividness reports. Also, a reduction of the vagal control, which is the typical autonomic correlate of MI, was observed during both imagery tasks only in Highs. Conclusions: These findings indicate a cross-talk between the cardiovascular control and the proprioceptive representation of movement and reinforce the theory of bi-directional communication between heart and brain.