The role of ongoing oscillations in pain perception: absence of modulation by an arithmetic task

Details

Supervisors

Liberati, Giulia ; Leu, Chiara

Faculty

Faculté de pharmacie et des sciences biomédicales

Degree label

Master [120] en sciences biomédicales, à finalité approfondie

Abstract

To this date, the exact neural mechanisms underlying pain perception have not yet been unraveled. Previous work has suggested a relationship between nociception and ongoing neural oscillations. However, whether these modulations play a significant role in the perception of sustained pain remains unclear. To clarify this, we investigated whether distraction - an attentional state known to affect pain perception - also modulates the amplitude of ongoing neural oscillations. For this purpose, we used scalp electroencephalography (EEG) to record the brain activity of 25 healthy volunteers who received periodic sustained thermonociceptive and vibrotactile stimulations during a baseline condition (i.e., no specific instruction) and while performing a distraction task (i.e., an arithmetic task). We “tagged” the responses elicited by sustained thermonociceptive and vibrotactile stimulations using the frequency at which the intensity of the stimuli was periodically modulated (0.2 Hz). In line with our hypothesis, both stimulations elicited a periodic EEG response and a periodic modulation of ongoing EEG oscillations at the frequency of stimulation (0.2 Hz) and its harmonics. As expected, the distraction task led to a decrease in the perceived intensity of both the thermoniceptive and the vibrotactile stimuli. However, the periodic EEG response and the periodic modulations of ongoing oscillations were not affected by the distraction task. Therefore, the magnitude of the periodic response and the modulation of ongoing oscillations appear to be dissociated from the magnitude of the perception. Nevertheless, it's worth noting that the effect of the arithmetic task during thermonociceptive stimulation was smaller than during vibrotactile stimulation. It would thus be interesting to assess whether another task with a higher distraction effect would lead to different results.