Repetitive Passive Movement Modulates Corticospinal Excitability: Effect of Movement and Rest Cycles and Subject Attention.

Shota Tsuiki,Kei Saito,Manh Van Pham,Ryoki Sasaki,Sho Kojima,Naofumi Otsuru,Hideaki Onishi,Yasuto Inukai,Shota Miyaguchi

doi:10.3389/fnbeh.2019.00038

Abstract

Repetitive passive movement (PM) affects corticospinal excitability; however, it is unknown whether a duty cycle which repeats movement and rest, or subjects’ conscious attention to movements, affects corticospinal excitability. We aimed to clarify the effect of the presence or absence of a duty cycle and subjects’ attention on corticospinal excitability. Three experiments were conducted. In Experiment 1, PM of the right index finger was performed for 10 min. Three conditions were used: (1) continuous PM (cPM) at a rate of 40°/s; (2) intermittent PM (iPM) with a duty cycle at 40°/s; and (3) iPM at 100°/s. In conditions 1 and 3, motor evoked potential (MEP) amplitude was significantly reduced. In Experiment 2, PM was performed for 30 min: condition 1 comprised cPM at a rate of 40°/s and Condition 2 comprised iPM at 40°/s. MEP amplitude significantly decreased in both conditions. In Experiment 3, PM was performed for 10 min: condition 1 comprised paying attention to the moving finger during iPM and Condition 2 was similar to Condition 1 but while counting images on a monitor without looking at the movement finger, and Condition 3 comprised counting images on a monitor without performing PM. MEP amplitude significantly increased only under Condition 1. Thus, afferent input from movements above a certain threshold may affect corticospinal excitability reduction. Furthermore, corticospinal excitability increases when paying attention to passive finger movement.

Highlights

Corticospinal excitability decreases after passive movement (PM; Otsuka et al, 2017; Sasaki et al, 2017); this is thought to be due to post-exercise depression (PED)
In Experiment 3, we hypothesized that directing attention to the PM of index fingers would induce an increase in corticospinal excitability, and we aimed to clarify the influence of paying attention to repetitive PM on corticospinal excitability
Because the main effect of the TIME factor was significant, post hoc test was performed using the average results from the two conditions and found a significant decrease in motor evoked potential (MEP) in Post-0, Post-5, and Post-10 compared with Pre (P < 0.01)

Summary

Introduction

Corticospinal excitability decreases after passive movement (PM; Otsuka et al, 2017; Sasaki et al, 2017); this is thought to be due to post-exercise depression (PED). Passive Movement Modulates Corticospinal Excitability of suppressive circuits in the cortex (Sasaki et al, 2017). This phenomenon may be due to a decrease in the primary motor cortex (M1) activity. Corticospinal excitability increases with PM (Macé et al, 2008) and remains unchanged (Lotze et al, 2003). This fluctuation in corticospinal excitability is thought to be influenced by differences in various stimuli such as the duration of movement, speed of movement, presence or absence of a duty cycle of repeated movement and rest, and presence or absence of a subject’s active attention on the movement

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