Effects of Rubber Hand Illusion and Excitatory Theta Burst Stimulation on Tactile Sensation: A Pilot Study

Neural Plasticity, 2020 · DOI: https://doi.org/10.1155/2020/3069639 · Published: April 1, 2020

Simple Explanation

This study explores how stimulating the brain with a technique called transcranial magnetic stimulation (rTMS) affects how we feel touch, especially when combined with a visual trick called the rubber hand illusion (RHI). The RHI makes people feel like a rubber hand is their own. The researchers tested whether using rTMS to increase brain activity in the area that processes touch (S1) could enhance the effects of the RHI on tactile sensation. They compared real and sham (fake) versions of both rTMS and the RHI. The study involved healthy participants and one patient with a spinal cord injury to see if the combination of rTMS and RHI could improve their sense of touch.

Study Duration

Not specified

Participants

21 healthy subjects and one patient with cervical spinal cord injury

Evidence Level

Level 3; Cross-over, placebo-controlled, single-blind study

Key Findings

1
The rubber hand illusion (RHI) itself had a strong effect on participants' sense of touch and body ownership.
2
Excitatory rTMS over S1 seemed to disrupt or inhibit the effects of the RHI, possibly by strengthening the brain's normal top-down and bottom-up connections.
3
The spinal cord injury (SCI) patient showed a greater response to the RHI alone compared to healthy participants, suggesting that the RHI may be particularly effective in individuals with impaired sensation.

Research Summary

This pilot study investigated the effects of combining the rubber hand illusion (RHI) with high-frequency repetitive transcranial magnetic stimulation (rTMS) on tactile sensation in healthy subjects and one patient with spinal cord injury. The results suggest that rTMS of the primary sensory region (S1) may inhibit the effects of the RHI, potentially by enhancing top-down and bottom-up connections in the brain. The RHI alone showed promise in improving tactile sensation, particularly in the spinal cord injury patient, indicating its potential as a therapeutic approach for individuals with impaired sensation.

Practical Implications

Therapeutic Potential of RHI

The RHI could be a promising therapeutic method for improving tactile sensation in patients with impaired sensation, especially those with spinal cord injuries.

Modulation of Brain Stimulation

The type of brain stimulation (excitatory vs. inhibitory) may have different effects on the RHI and tactile sensation, suggesting the need for tailored approaches.

Understanding Body Ownership

The study contributes to understanding the neural mechanisms underlying body ownership and the interplay between top-down and bottom-up processing in sensory perception.

Study Limitations

1
Small sample size, particularly the inclusion of only one patient with SCI.
2
The method of navigating S1 from the motor hot spot, rather than using neuronavigation, may have introduced variability.
3
The study only stimulated S1, while other brain areas involved in body ownership may also play a role.

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