WITHDRAWN: Motor imagery and the muscle system

Abstract

Many studies have investigated the activation of cortical areas and corticospinal excitability during motor imagery (MI) in relation to motor execution. Similar activation of cortical areas during imagined and executed bodily movements as well as increased corticospinal excitability while MI has been demonstrated. Despite these similarities on the central nervous level, there is no overt movement during MI. This suggests that the centrally generated signals must be inhibited at some level. Second, even in the absence of movement, some studies find behavioral effects of MI interventions. Most of the studies have investigated the role of MI on the cortical or spinal level, but less is known about the peripheral level, such as the muscle system. Testing muscular excitability during MI will give further hints whether and how low-threshold motor commands during MI reach the muscular system. Furthermore, the extent of the shown effects during imagery depends considerably on type of imagery, available proprioceptive information, and imagery ability. Therefore, this study investigates muscular excitability of the biceps brachii muscle manipulating imagery mode (MI vs. visual imagery) and proprioceptive information (with or without muscle effort). The mechanical response of the muscle after a single electrical stimulus will be assessed via tensiomyography (TMG). This technique can be used to test muscular excitability independently from spinal effects. The influence of imagery mode and muscle effort on TMG parameters will be analyzed with consideration of a possible modulation by imagery ability. The results will elucidate whether and how the peripheral muscle system responds during MI.