Dissociation between pain and the nociceptive blink reflex during psychological arousal.
OBJECTIVE
To investigate the effect of psychological arousal on pain ratings and the R2 component of the electrically evoked blink reflex to a 'pure' noiciceptive stimulus.


METHODS
Pain ratings and R2 to a noiciceptive stimulus (pulse width 0.3ms, 2mA, delivered from a concentric electrode attached to the supraorbital region of the forehead) were investigated in 16 healthy participants before and during a serial subtraction task, and in 16 control participants who sat quietly during nociceptive stimulation.


RESULTS
Pain ratings decreased whereas R2 amplitude increased during the serial subtraction task.


CONCLUSIONS
Supra-spinal rather than spinal mechanisms inhibited pain perception during psychological arousal. Moreover, psychological arousal facilitated the R2 component of the blink reflex to a nociception-specific stimulus.


CONCLUSIONS
Supra-spinal influences need to be considered during clinical evaluation of the trigeminal nociceptive blink reflex.
Koh
Chee Wan
CW
School of Psychology, Murdoch University, South Street, Murdoch, Perth, WA 6150, Australia.
Drummond
Peter D
PD
D000328:Adult; D000344:Afferent Pathways / Q000502:physiology; D001143:Arousal / Q000502:physiology*; D001767:Blinking / Q000502:physiology*; D001921:Brain / Q000502:physiology; D004525:Efferent Pathways / Q000502:physiology; D004558:Electric Stimulation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009433:Neural Inhibition / Q000502:physiology; D009619:Nociceptors / Q000502:physiology*; D010146:Pain / Q000503:physiopathology* / Q000523:psychology*; D010147:Pain Measurement; D017288:Pain Threshold; D013116:Spinal Cord / Q000502:physiology; D014276:Trigeminal Nerve / Q000502:physiology