Abstract

The nociceptive withdrawal reflex (NWR), a defensive response that allows withdrawal from a noxious stimulus, is a reliable index of spinal nociception in humans. It has been shown that various kinds of stimuli (emotional, visual, auditory) can modulate the transmission and perception of pain. The aim of the present study was to evaluate, by means of the NWR, the modulatory effect on the spinal circuitry of olfactory stimuli with different emotional valence. The magnitude of the NWR elicited by electrical stimulation of the sural nerve was measured while 18 subjects (9 women, 9 men) smelled pleasant, unpleasant, or neutral odors. The NWR was conditioned by odor probe with interstimulus intervals (ISIs) of 500 ms and 1,500 ms. The magnitude of NWR was significantly greater after the unpleasant odor probe (P <.001) and reduced following the pleasant odor probe (P<.001) at both ISIs. A significant effect of olfactory stimuli on subjective pain ratings were found at both ISIs for pleasant vs unpleasant odors (P<.000), and for both pleasant and unpleasant odors vs neutral and basal conditions (P<.000). No statistical differences in subjective pain ratings at different ISIs were found. Consistent with the notion that NWR magnitude and pain perception can be modulated by stimuli with different emotional valence, these results show that olfactory stimuli, too, can modulate spinal nociception in humans.

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.