Baroreceptor activation attenuates attentional effects on pain-evoked potentials.
Focused attention typically enhances neural nociceptive responses, reflected electroencephalographically as increased amplitude of pain-evoked event-related potentials (ERPs). Additionally, pain-evoked ERPs are attenuated by hypertension and baroreceptor activity, through as yet unclear mechanisms. There is indirect evidence that these two effects may interact, suggesting that baroreceptor-related modulation of nociception is more than a low-level gating phenomenon. To address this hypothesis, we explored in a group of healthy participants the combined effects of cue-induced expectancy and baroreceptor activity on the amplitude of pain-evoked ERPs. Brief nociceptive skin stimuli were delivered during a simple visual task; half were preceded by a visual forewarning cue, and half were unpredictable. Nociceptive stimuli were timed to coincide either with systole (maximum activation of cardiac baroreceptors) or with diastole (minimum baroreceptor activation). We observed a strong interaction between expectancy and cardiac timing for the amplitude of the P2 ERP component; no effects were observed for the N2 component. Cued stimuli were associated with larger P2 amplitude, but this effect was abolished for stimuli presented during baroreceptor activation. No cardiac timing effect was observed for un-cued stimuli. Taken together, these findings suggest a close integration of cognitive-affective aspects of expectancy and baroreceptor influences on pain, and as such may cast further light on mechanisms underlying mental and physiological contributions to clinical pain.
Clinical Imaging Sciences Centre (CISC), Brighton and Sussex Medical School (BSMS), University of Sussex, Brighton, East Sussex, BN1 9RR, UK Experimental Neuropsychology Research Unit, School of Psychology and Psychiatry, Monash University 3800, Australia Scientific Department, Fondazione IRCCS Istituto Neurologico "Carlo Besta", Milano, Italy Department of Physiology, University of Siena, Italy Sussex Partnership Foundation (NHS) Trust, Sussex, UK.
Marcus A
MA
Gray
Ludovico
L
Minati
Giulia
G
Paoletti
Hugo D
HD
Critchley
D000328:Adult; D000704:Analysis of Variance; D001288:Attention / Q000502:physiology*; D001794:Blood Pressure / Q000502:physiology; D001931:Brain Mapping; D004558:Electric Stimulation; D004569:Electroencephalography; D005073:Evoked Potentials, Somatosensory / Q000502:physiology*; D005260:Female; D006801:Humans; D010146:Pain / Q000503:physiopathology*; D010147:Pain Measurement; D058748:Pain Perception / Q000502:physiology*; D010775:Photic Stimulation; D011311:Pressoreceptors / Q000503:physiopathology*; D011930:Reaction Time / Q000502:physiology; D014796:Visual Perception / Q000502:physiology