Martins, Amadeu Manuel Quelhas (2011)
Ph.D. thesis, University of Birmingham.
Afferent feedback from arterial baroreceptors modulates sensorimotor responses, but it is unknown whether it can also interfere with high-order cognition. In Study One, electrocutaneous stimuli (ranging from non-painful to very painful) were randomly delivered across the cardiac cycle. Pain ratings were highest at R+300 ms, whereas nociceptive reflex responses did not vary. Study Two followed up these findings by presenting the stimuli in blocks of either ascending or descending intensities. Nociceptive responses to painful stimuli were attenuated during systole; pain ratings did not vary regardless of stimulus intensity. Study Three compared both schedules of stimulation independently of cardiac cycle timings. When unpredictable, shocks elicited hypoalgesia but also the highest nociceptive responses, indicating that pain dissociates from nociception under stress. The fourth study examined the effects of moderate exercise-induced cardiovascular arousal on attention control and working memory. Two experiments revealed that working memory and attention are facilitated by moderate exercise. Finally, Study Five assessed Sternberg task performance across the cardiac cycle. Probes presented during systole produced the highest intercept but the shallowest slope. In sum, these studies (a) provide further support for the afferent feedback hypothesis; and (b) extend previous findings obtained with sensorimotor responses to high-order cognition.
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