Figures and data
Experimental design.
(A) Experimental procedure. All subjects completed a laser energy evaluation, pre-training pain assessment, NFB training, and post-training pain assessment. (B) Pain assessment before and after NFB training. Ten laser pulses were delivered to the dorsum of the right hand, with pain intensity and unpleasantness ratings recorded before and after NFB training for each participant. (C) Three sessions of NFB training. During each training session, EEG and EMG (in the second part of the experiment) data were recorded, while subjects watched a video and received nociceptive laser stimuli. After each session, subjects rated their pain intensity and unpleasantness. (D) Laser pulses delivered during NFB training. Forty laser stimuli were delivered to the dorsum of the participant’s right hand in each NFB training session.
Neurofeedback (NFB) training system.
(A) Experimental setup. The participant sat comfortably in a chair, wearing headphones, and maintained a fixed gaze on a computer monitor positioned 30 cm away while watching a video. Nociceptive laser stimuli were delivered to the dorsum of the participant’s right hand. Throughout the entire NFB training, real-time EEG and EMG (in the second part of the experiment) signals were recorded, processed, and used to provide feedback to the participant. (B) Technical implementation diagram. The system consisted of three modules: EEG recording, gamma power calculation, and visual feedback.
Spontaneous gamma oscillation changes during neurofeedback (NFB) training.
(A) PSD of spontaneous EEG oscillations during three NFB training sessions for both active (left) and sham (right) groups, along with scalp topographies of statistical F values for gamma oscillations (30-60Hz). Electrodes with significant effects are marked with white dots (FDR correction, p < 0.05). (B) Comparisons of spectral powers of spontaneous gamma oscillations across three NFB training sessions for both groups. (C) Correlations between spectral powers of spontaneous gamma oscillations and pain intensity ratings in three NFB training sessions for the active group. Error bars represent standard errors. *: p < 0.05; ***: p < 0.001
Subjective pain intensity and unpleasantness changes induced by neurofeedback (NFB) training.
(A) Comparisons of subjective ratings of pain intensity (left) and unpleasantness (right) across three NFB training sessions for both groups. (B) Comparisons of subjective ratings of pain intensity (left) and unpleasantness (right) before and after NFB training for both groups. Error bars represent standard errors. *: p < 0.05; **: p < 0.01; ***: p < 0.001.
Group-level laser-evoked potentials (LEPs) during neurofeedback (NFB) training.
(A) Group-level LEP waveforms at Cz (referenced to bilateral mastoids) and scalp topographies of N2 and P2 waves during three NFB training sessions for both active (left) and sham (right) groups. (B) Comparisons of N2, P2, N2-P2 peak-to-peak amplitudes across three NFB training sessions for both groups. Error bars represent standard errors. *: p < 0.05; **: p < 0.01; ***: p ≤ 0.001.
Correlations between gamma power at Pz and that recorded from the EMG electrode.
No significant correlations were found in either the active or sham group across sessions, indicating that the modulation of gamma power at Pz is unlikely to reflect muscle activity.
