Repetitive Transcranial Magnetic Stimulation (rTMS) Improves the Gait Disorders of Rats Under Simulated Microgravity Conditions Associated With the Regulation of Motor Cortex

Frontiers in Physiology, 2021 · DOI: 10.3389/fphys.2021.587515 · Published: February 4, 2021

Simple Explanation

This study investigates whether repetitive transcranial magnetic stimulation (rTMS) can help with walking problems caused by simulated microgravity (SM) in rats. SM can lead to gait disorders, and the study aims to see if rTMS can be a potential treatment. The experiment involved exposing rats to SM for 21 days, while also applying high-frequency rTMS for 14 days. The results showed that SM caused walking difficulties in rats, but rTMS could reverse these effects. Furthermore, rTMS affected the brain activity in the motor cortex, specifically enhancing certain brain waves (δ band) and suppressing others (θ and α bands). It also activated a protein called mTOR in the motor cortex. These findings suggest that rTMS improves walking by regulating brain activity and activating motor-related proteins.

Study Duration

3 weeks

Participants

Male Wistar rats (180–220 g)

Evidence Level

Not specified

Key Findings

1
SM could cause gait disorders such as decreased walking ability and contralateral limb imbalance in rats, which could be reversed by rTMS.
2
rTMS affected the neural oscillations of motor cortex, enhancing in δ (2–4 Hz) band, suppressing in θ (4–7 Hz), and α (7–12 Hz) bands.
3
rTMS could activate mTOR in the motor cortex, suggesting the improvement effects of rTMS on gait disorders in rats under SM conditions might be associated with its regulation on neural oscillations in the cerebral motor cortex.

Research Summary

The study evaluated the effects of rTMS on rat gait function under simulated microgravity (SM) conditions. SM was induced for 21 days, with rTMS applied for 14 days starting on the eighth day of SM. Behavioral results indicated that SM led to gait disorders, including decreased walking ability and contralateral limb imbalance, which rTMS could reverse. rTMS also modulated neural oscillations in the motor cortex and activated mTOR. The findings suggest that rTMS improves gait disorders under SM by regulating neural oscillations in the motor cortex and influencing the expression of motor-related proteins, potentially enhancing nervous system control over muscle function.

Practical Implications

Potential Clinical Application

rTMS can be used as an potential effective supplement in the ﬁeld of clinical and rehabilitation research to reduce gait disorders caused by the space environment.

Understanding rTMS Mechanisms

The results contribute to a deeper understanding of the possible electrophysiological and molecular mechanisms underlying the effects of rTMS on the brain.

Therapeutic Target

mTOR can be an attractive therapeutic target and deserves further investigations to enhance neuronal activity and improve gait disorders.

Study Limitations

1
Changes in body weight may have been caused by modeling effects on feeding and excretion in rats.
2
There is still myasthenia in the hind limbs that was not alleviated.
3
The relative contribution of nerve and muscle factors in motor improvement has not been thoroughly understood during rTMS treatment.

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