Influence of pain on motor preparation in the human brain

Abstract

The protective function of pain depends on appropriate motor responses to avoid injury and promote recovery. The preparation and execution of motor responses is thus an essential part of pain. However, it is not yet fully understood how pain and motor processes interact in the brain. Here we used electroencephalography to investigate the effects of pain on motor preparation in the human brain. Twenty healthy human participants performed a motor task in which they performed button presses to stop increasingly painful thermal stimuli when they became intolerable. In another condition, participants performed button presses without concurrent stimulation. The results show that the amplitudes of preparatory event-related desynchronizations at alpha and beta frequencies did not differ between conditions. In contrast, the amplitude of the preparatory readiness potential was reduced when a button press was performed to stop a painful stimulus compared with a button press without concomitant pain. A control experiment with nonpainful thermal stimuli showed a similar reduction of the readiness potential when a button press was performed to stop a nonpainful thermal stimulus. Together, these findings indicate that painful and nonpainful thermal stimuli can similarly influence motor preparation in the human brain. Pain-specific effects on motor preparation in the human brain remain to be demonstrated. Pain is inherently linked to motor processes, but the interactions between pain and motor processes in the human brain are not yet fully understood. Using electroencephalography, we show that pain reduces movement-preparatory brain activity. Further results indicate that this effect is not pain specific but independent of the modality of stimulation.

Effect of movement‐related pain on behaviour and corticospinal excitability changes associated with arm movement preparation

“…readiness potential) (Postorino et al . ). The second study reported that in the presence of pain, externally cued movements are initiated faster, and this is associated with a suppression of premotor cortex beta oscillations in the EEG (Misra et al .…”

“…The first study demonstrated that self-initiated movements performed to stop a painful stimulation are preceded by a lower amplitude of the movement-preparatory brain activity (i.e. readiness potential) (Postorino et al 2017). The second study reported that in the presence of pain, externally cued movements are initiated faster, and this is associated with a suppression of premotor cortex beta oscillations in the EEG (Misra et al 2017).…”

Recent advances in objectifying pain using neuroimaging techniques

“…These observations are ground breaking as they suggest a distinction between the cortical representation of pain, which is spatially independent (as cortical representation is the same for right/left hand stimulation), and stimuli intensity, which is spatially dependent (cortical representation is contralateral to the stimulated hand). These results display cortical representation for a key symptom of chronic pain conditions (i.e., dissociation between perceived pain and presented pain) (Nickel et al 2017). Pain perception from shorter bouts of noxious thermal impulses (4 s) has further been shown to be associated with an increase in GBO in the mPC (Misra et al 2017).…”

“…Contrasting, high-frequency brain oscillations (i.e., gamma) are more rapid and focal (Fardo et al 2017). Notable for their application of a long duration noxious thermal stimuli (tonic heat), Nickel and colleagues (Nickel et al 2017) reported higher pain intensity ratings [using the 0 -10 numeric rating scale (NRS) where 0 represents no pain and 10 represents the worst pain possible] corresponding with stronger GBO in the medial prefrontal cortex (mPC) for both right/left hand stimulation (Fig. 1A).…”

A modality selective effect of functional laterality in pain detection sensitivity

“…To avoid potential dangers, the vast majority of animals, including humans, use their senses to detect transient and sudden changes in their environments 1 , 2 . This function is critical to survival as the prompt detection of abrupt changes is crucial to determine the appropriate and immediate reaction to potential threats 3 – 6 . Regardless of the modality of sensory inputs, transient changes can elicit a series of brain responses, and the dominant part of the brain responses is a negative–positive biphasic vertex wave in the human electroencephalogram (EEG) 7 , 8 .…”