Exercise and microstructural changes in the motor cortex of older adults

Abstract

Exercise has been shown to counteract age-related volume decreases in the human brain, and in this imaging study, we ask whether the same holds true for the microstructure of the cortex. Healthy older adults (n = 47, 65-90 years old) either exercised three times a week on a stationary bike or maintained their usual physical routine over a 12-week period. Quantitative longitudinal relaxation rate (R 1 ) magnetic resonance imaging (MRI) maps were made at baseline and after the 12-week intervention. R 1 is commonly taken to reflect cortical myelin density. The change in R 1 (ΔR 1 ) was significantly increased in a region of interest (ROI) in the primary motor cortex containing motor outputs to the leg musculature in the exercise group relative to the control group (p = .04). The change in R 1 in this ROI correlated with an increase in oxygen consumption at the first ventilatory threshold (VT1) (p = .04), a marker of improvement in submaximal aerobic performance. An exploratory analysis across the cortex suggested that the correlation was predominately confined to the leg representation in the motor cortex. This study suggests that microstructural declines in the cortex of older adults may be staved off by exercise. K E Y W O R D Saging, cerebral cortex, exercise, humans, magnetic resonance imaging, microstructure, myelin, quantitative MRI 1712 | ROWLEY Et aL.

Regional cortical perfusion increases induced by a 6-month endurance training in young sedentary adults

“…These data from healthy older adults (age range of 65-90 years) who exercised three times per week or maintained their usual physical routine over a 12-week period suggest plasticity at the microstructural level. Similar to our results, the effects correlated with a marker of improvement in submaximal aerobic performance (Rowley et al, 2020). Our results are also consistent with work in adult rats trained with the running wheel for 30 days, indicating capillary growth in motor areas of the cerebral cortex as an adaptation to sustained motor activity (Swain et al, 2003).…”

“…The results are consistent with the concepts of promoting motor function through movement, as proposed by Perrey (2013) . More recently, somatotopically restricted changes in the leg representation of the primary motor cortex after exercise have been described using quantitative longitudinal relaxation rate (R1) MRI, where R1 reflects cortical myelin density ( Rowley et al, 2020 ). These data from healthy older adults (age range of 65–90 years) who exercised three times per week or maintained their usual physical routine over a 12-week period suggest plasticity at the microstructural level.…”

Deducing the Impact of Physical Activity, Sedentary Behavior, and Physical Performance on Cognitive Function in Healthy Older Adults

“…One of the most relevant mechanisms for PA and SB effects on CF is the alteration of cardiorespiratory fitness (CRF). Studies were able to show an association between CRF, CF and underlying brain metabolic adaptations in older adults (Newson and Kemps, 2006 ; Erickson et al, 2009 , 2012 ; Engeroff et al, 2018 , 2019 ; Rowley et al, 2020 ). Rowley et al ( 2020 ) could show microstructural changes in the motor cortex which where correlated to the oxygen consumption at the first ventilatory threshold after endurance training in older adults.…”

“…Studies were able to show an association between CRF, CF and underlying brain metabolic adaptations in older adults (Newson and Kemps, 2006 ; Erickson et al, 2009 , 2012 ; Engeroff et al, 2018 , 2019 ; Rowley et al, 2020 ). Rowley et al ( 2020 ) could show microstructural changes in the motor cortex which where correlated to the oxygen consumption at the first ventilatory threshold after endurance training in older adults. Engeroff et al ( 2018 ) found that brain derived neurotrophic factor (BDNF) was detrimentally associated with SB but beneficially related to accelerometer total activity counts and MVPA.…”

Alterations in white matter microstructural properties after lingual strength exercise in patients with dysphagia

“…The integrity of motor cortical pathways and connectivity are essential to the execution of motor function in the periphery, and these pathways can be impacted by age [3] and disease [4]. Literature focused on rehabilitation of limb function indicates that exercise can impact the cortical representation of the targeted region in older individuals [5], which could contribute to improved motor function. Thus, determining if lingual strengthening exercise is capable of impacting cortical structure and connectivity will be critical for better understanding the neurophysiological underpinnings of lingual strengthening exercise to allow for refining and optimizing this therapeutic approach.…”