Abstract
Purpose: Previously (VSS 2013), we reported a surprising relationship between two seemingly independent sensory modalities, namely human vision and pain. Specifically, adults' ability to tolerate heat and pressure pain was negatively correlated with performance on tests of spatial contrast sensitivity (CS). However, this effect was found only within a limited sample of adults who were tested repeatedly in order to reduce intra-subject variability. To better assess the robustness of this effect, and to explore the possible neural mechanisms that may underlie sensory interactions, we evaluated the relationship between pain and vision (both spatial and temporal) in a much larger group of young adults. Methods: Measures of spatial contrast sensitivity (FACT, Vector Vision, Rabin) and temporal photopic and mesopic flicker fusion thresholds were assessed binocularly in 105 healthy young adults (M = 23 yr; 62 females, 43 males). Within the same session, threshold and tolerance to both contact heat (arm) and pressure pain (pinky finger) were also assessed. Results: Correlational analyses revealed a strong relationship between all measures of CS and heat pain tolerance (all r > - 0.65), although results for pressure pain were more modest. Specifically, those who showed lower tolerance for heat pain (were more sensitive to pain) also showed higher levels of contrast sensitivity. Conversely, measures of critical flicker fusion thresholds appeared unrelated to any of the pain measures. Conclusions: Human adults show a relationship between heat pain sensitivity and spatial vision, but not between pain and the present measures of temporal vision. Given that dopamine is heavily involved in the processing of both pain and spatial information in the CNS, this raises the interesting possibility that the observed co-variation in sensitivity may be explained by dopaminergic involvement.
Meeting abstract presented at VSS 2014