A modality selective effect of functional laterality in pain detection sensitivity

Huijuan Zhang,Yanzhi Bi,Li Hu,Xuejing Lu

doi:10.1038/s41598-021-85111-x

Abstract

The ability to detect environmental changes is essential to determine the appropriate reaction when facing potential threats. Both detection and reaction functions are critical to survival, and the superior performance of motor reaction for the dominant hand is well recognized in humans. However, it is not clear whether there exists laterality in sensitivity to detect external changes and whether the possible laterality is associated with sensory modality and stimulus intensity. Here, we tested whether the perceptual sensitivity and electrophysiological responses elicited by graded sensory stimuli (i.e., nociceptive somatosensory, non-nociceptive somatosensory, auditory, and visual) that were delivered on/near the left and right hands would be different for right-handed individuals. We observed that perceived intensities and most brain responses were significantly larger when nociceptive stimuli were delivered to the left side (i.e., the non-dominant hand) than to the right side (i.e., the dominant hand). No significant difference was observed between the two sides for other modalities. The higher sensitivity to detect nociceptive stimuli for the non-dominant hand would be important to provide a prompt reaction to noxious events, thus compensating for its worse motor performance. This laterality phenomenon should be considered when designing experiments for pain laboratory studies and evaluating regional sensory abnormalities for pain patients.

Highlights

To test these research hypotheses, we elucidated whether the perceptual sensitivity and electrophysiological responses elicited by transient sensory stimuli that were delivered on or near the left and right hands would be different for right-handed individuals
Post hoc paired-sample t-tests were conducted to break down the significant interaction between “sensory modality” and “stimulus side”, and the results showed that the perceived intensity to nociceptive somatosensory stimuli delivered to the left side was significantly larger than to the right side (p = 0.010), while such significant side effect was not found in non-nociceptive somatosensory, auditory, or visual modality (p = 0.336, 0.644, and 0.232, respectively; Fig. 1A)
One of the main findings of the present study is that the perceived intensities and almost all brain responses were consistently larger when nociceptive somatosensory stimuli were delivered to the left side than to the right side (Figs. 1, 2, 3, 4)

Summary

Introduction

To test these research hypotheses, we elucidated whether the perceptual sensitivity and electrophysiological responses elicited by transient sensory stimuli that were delivered on or near the left and right hands would be different for right-handed individuals. Graded sensory stimuli belonging to four different modalities (i.e., nociceptive somatosensory, non-nociceptive somatosensory, auditory, and visual) were delivered to a large number of healthy subjects (63 females and 37 males, 100 subjects in total) to assess whether the laterality phenomenon was associated with sensory modality and stimulus intensity

Methods

Results

Discussion

Conclusion