Attention to a painful cutaneous laser stimulus modulates electrocorticographic event-related desynchronization in humans.

Objective: To test the hypothesis that attention to painful cutaneous laser stimuli enhances event-related desynchronization (ERD) in cortical regions receiving nociceptive input.

Methods: We used wavelet time-frequency analysis and bandpass filtering to measure ERD quantitatively in subdural electrocorticographic recordings while subjects either attended to, or were distracted from, a painful cutaneous laser stimulus.

Results: ERD were observed over primary somatosensory and parasylvian (PS) cortices in all 4 subjects, and over medial frontal cortex in 1 subject. Laser-evoked potentials were also observed in all 3 regions. In all subjects, ERD was more widespread and intense, particularly over PS, during attention to laser stimuli (counting stimuli) than during distraction from the stimuli (reading for comprehension).

Conclusions: These findings suggest that pain-associated ERD is modulated by attention, particularly over PS. Conclusions: This study suggests that thalamocortical circuits are involved in attentional modulation of pain because of the proposed role of these circuits in the mechanisms of ERD.