Influence of Physical Exercise on Neuroplasticity and Sensorimotor Networks in Older Adults

Condition(s) studied

Investigational drug(s) / intervention(s)

Aerobic Exercise: Participants perform 20 minutes of moderate-intensity cycling on a cycle ergometer at 50% of heart rate reserve, maintaining a cadence between 60 and 70 revolutions per minute (rpm).

Physical Inactivity: Participants remain seated for 20 minutes while watching a silent video of natural waterfall scenes without narration.

Transcranial Magnetic Stimulation: Single- and paired-pulse TMS is applied over the primary motor cortex (M1) to assess corticospinal excitability and intracortical inhibitory and facilitatory mechanisms and sensorimotor circuit function. Motor evoked potentials (MEPs) are recorded from the abductor pollicis brevis (APB) muscle of the dominant hand.

transcranial direct current stimulation: Anodal transcranial direct current stimulation (tDCS) is delivered for 20 minutes over the primary motor cortex (M1) at a current intensity of 2mA.

Study summary

The purpose of this study is to investigate the influence of a single session of moderate aerobic exercise on motor cortex neuroplasticity in older adults, both alone and in combination with transcranial direct current stimulation (tDCS), and to compare these effects with those observed in young adults.

Normal aging is associated with changes in the central nervous system that can affect motor function, sensorimotor integration, and cortical inhibitory mechanisms. These alterations may reduce the brain's capacity for neuroplasticity, which is essential for motor learning and functional adaptation. Physical exercise has been proposed as a potential strategy to counteract age-related decline in neuroplasticity.

In this study, healthy young and older adults will participate in three experimental sessions. Participants will complete two experimental conditions in a randomized crossover design: (1) aerobic exercise followed by transcranial direct current stimulation (tDCS), and (2) physical inactivity followed by tDCS and a third session will assess the effects of exercise alone. Moderate aerobic exercise will consist of 20 minutes of cycling on an ergometer.

Corticospinal excitability and intracortical and sensorimotor circuit function will be assessed using transcranial magnetic stimulation (TMS) before and after each intervention. Neuroplasticity will be evaluated by measuring changes in motor evoked potentials recorded from a hand muscle of the dominant side.

The primary objective is to determine whether aerobic exercise enhances tDCS-induced plasticity, and whether this enhancement differs between young and older adults. Secondary objectives include evaluating age-related differences in intracortical inhibitory and facilitatory mechanisms and sensorimotor integration processes.

By improving understanding of how exercise interacts with brain stimulation to modulate motor cortex plasticity, this study may help inform strategies aimed at preserving motor function and functional independence in aging populations.

Eligibility

Primary outcome measure(s)

• Corticospinal excitability — Assessed at baseline and immediately post-intervention during each of the three experimental sessions (aerobic exercise + tDCS, physical inactivity + tDCS and aerobic exercise alone).
  Corticospinal excitability will be assessed using transcranial magnetic stimulation (TMS) applied to the primary motor cortex. Motor evoked potentials (MEPs) are recorded using surface electromyography from the abductor pollicis brevis (APB) muscle of the dominant hand. Single pulses of increasing intensity will be delivered to establish an input-output (I/O) recruitment curve. The stimulation intensity will be increased in steps of 3 to 5%, and 10 stimuli will be delivered per stimulation intensity. I/O curves will be fitted using a Boltzmann sigmoid function. Three parameters will be derived : slope, plateau and S50. These parameters will be compared across experimental conditions. The primary outcome will be the slope of the I/O curve, reflecting the recruitment rate of neurons in the corticospinal tract, indicating the level of corticospinal excitability.

Trial sites (1)

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