The effect of breaking up prolonged sitting on paired associative stimulation-induced plasticity

• Published in: Experimental brain research Vol. 238; no. 11; pp. 2497 - 2506
• Main Authors: Bojsen-Møller, E., Ekblom, M. M., Tarassova, O., Dunstan, D. W., Ekblom, O.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.11.2020; Springer
• Subjects: Biomedical and Life Sciences; Biomedicine; Corticospinal excitability; Exercise; Medicin/Teknik; Medicine/Technology; Neurology; Neurosciences; Paired associative stimulation; Physical fitness; Research Article; Sedentary behaviour; Transcranial magnetic stimulation; United Kingdom; Sweden; Corticospinal excitability; Transcranial magnetic stimulation; Sedentary behaviour; Paired associative stimulation
• ISSN: 0014-4819; 1432-1106; 1432-1106
• DOI: 10.1007/s00221-020-05866-z

Paired associative stimulation (PAS) can induce plasticity in the motor cortex, as measured by changes in corticospinal excitability (CSE). This effect is attenuated in older and less active individuals. Although a single bout of exercise enhances PAS-induced plasticity in young, physically inactive adults, it is not yet known if physical activity interventions affect PAS-induced neuroplasticity in middle-aged inactive individuals. Sixteen inactive middle-aged office workers participated in a randomized cross-over design investigating how CSE and short-interval intracortical inhibition (SICI) were affected by PAS preceded by 3 h of sitting (SIT), 3 h of sitting interrupted every 30 min by 3 min of frequent short bouts of physical activity (FPA) and 2.5 h of sitting followed by 25 min of moderate-intensity exercise (EXE). Transcranial magnetic stimulation was applied over the primary motor cortex (M1) of the dominant abductor pollicis brevis to induce recruitment curves before and 5 min and 30 min post-PAS. Linear mixed models were used to compare changes in CSE using time and condition as fixed effects and subjects as random effects. There was a main effect of time on CSE and planned within-condition comparisons showed that CSE was significantly increased from baseline to 5 min and 30 min post-PAS, in the FPA condition, with no significant changes in the SIT or EXE conditions. SICI decreased from baseline to 5 min post-PAS, but this was not related to changes in CSE. Our findings suggest that in middle-aged inactive adults, FPAs may promote corticospinal neuroplasticity. Possible mechanisms are discussed.