Mental imagery-induced attention modulates pain perception and cortical excitability.

Magdalena Sarah Volz,Vanessa Suarez-Contreras,Felipe Fregni,Andrea L Santos Portilla

doi:10.1186/s12868-015-0146-6

Abstract

BackgroundMental imagery is a powerful method of altering brain activity and behavioral outcomes, such as performance of cognition and motor skills. Further, attention and distraction can modulate pain-related neuronal networks and the perception of pain. This exploratory study examined the effects of mental imagery-induced attention on pressure pain threshold and cortical plasticity using transcranial magnetic stimulation (TMS). This blinded, randomized, and parallel-design trial comprised 30 healthy right-handed male subjects. Exploratory statistical analyses were performed using ANOVA and t-tests for pain and TMS assessments. Pearson’s correlation was used to analyze the association between changes in pain threshold and cortical excitability.ResultsIn the analysis of pain outcomes, there was no significant interaction effect on pain between group versus time. In an exploratory analysis, we only observed a significant effect of group for the targeted left hand (ANOVA with pain threshold as the dependent variable and time and group as independent variables). Although there was only a within-group effect of mental imagery on pain, further analyses showed a significant positive correlation of changes in pain threshold and cortical excitability (motor-evoked potentials via TMS).ConclusionsMental imagery has a minor effect on pain modulation in healthy subjects. Its effects appear to differ compared with chronic pain, leading to a small decrease in pain threshold. Assessments of cortical excitability confirmed that these effects are related to the modulation of pain-related cortical circuits. These exploratory findings suggest that neuronal plasticity is influenced by pain and that the mental imagery effects on pain depend on the state of central sensitization.

Highlights

Mental imagery is a powerful method of altering brain activity and behavioral outcomes, such as performance of cognition and motor skills
Based on data from invasive and noninvasive brain stimulation techniques, such as transcranial magnetic stimulation (TMS) (Figure 1b), there is a bidirectional relationship between pain and motor cortex excitability
We found that motor tasks, sensory stimuli, and movement observation can change pressure pain threshold levels and cortical excitability [10,27,28] (Figure 1c), in which active tasks for one hand can ameliorate the perception of pain in the targeted hand

Summary

Introduction

Mental imagery is a powerful method of altering brain activity and behavioral outcomes, such as performance of cognition and motor skills. Attention and distraction can modulate pain-related neuronal networks and the perception of pain. This exploratory study examined the effects of mental imagery-induced attention on pressure pain threshold and cortical plasticity using transcranial magnetic stimulation (TMS). This blinded, randomized, and parallel-design trial comprised 30 healthy right-handed male subjects. Based on data from invasive and noninvasive brain stimulation techniques, such as transcranial magnetic stimulation (TMS) (Figure 1b), there is a bidirectional relationship between pain and motor cortex excitability. We hypothesized that mental imagery that is focused toward a specific hand will significantly modify TMS-indexed cortical

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Results

Discussion

Conclusion