Biology subjects

Szikszay, T.

Publications and source records attributed to Szikszay, T..

3 recordsLinked to original sources

bioRxiv2024

Pain distribution can be determined by classical conditioning

ABSTRACTChronic widespread pain (CWP) - as many other clinical presentations - manifests in ongoing pain without identifiable structural cause, with pain that spreads over multiple body areas. The development and maintenance of symptoms may involve learning mechanisms. Ninety-four healthy volunteers participated in this study and were randomly distributed to four groups. In the classical conditioning combined with verbal suggestion group, US-(small pain distribution) and US+ (large pain distribution) were paired with visual stimuli (CS+ and CS-) and participants were told about this association. In the verbal suggestion group, the conditioning was not performed, whereas in classical conditioning only group, learning was not combined with suggestion. In the control group, conditioning and suggestion did not take place. Ratings of perceived pain distribution (PD) were collected after each trial and ratings of pain intensity after each block of trials. During the testing phase, participants were exposed to electrocutaneous stimuli corresponding to only the small (US-) pain distribution. Results showed significant differences between CS+ and CS-pain distribution ratings across the experimental groups: conditioning + verbal suggestion (p<0.01), conditioning only group (p<0.05) and verbal suggestion only group (p<0.05), but not in the control group (p>0.05). Furthermore, significant differences in the perceived pain distribution were found between the control group and all experimental groups. This result supports our main hypothesis that the perceived pain distribution can be influenced by classical conditioning as well as verbal suggestion, although the effect is stronger when both are combined.

physiology↗

bioRxiv2024

Experimentally induced pain and paresthesia respond differently to cuff-based compression

Neuropathic pain is a significant therapeutic challenge due to the co-occurrence with other neurological symptoms such as paresthesia. Human-based models such as cuff algometry can enhance our understanding of pain-paresthesia relationships. This experiment aimed to characterize (psychophysically) pain and paresthesia evoked by stimuli of different temporal and intensity parameters and to demonstrate the reliability of experimental induction of these two symptoms using cuff algometry. Forty participants, aged 18-35, were exposed to mechanical pressure stimuli at three intensities (100, 150, 200 mmHg) and three durations (90, 120, 150s). Skin Conductance (SC) was continuously monitored, and participants rated pain and paresthesia in real-time using a computerized visual analog scale. The General Linear Model analysis revealed significant differences in paresthesia across all durations (p<0.01), but not all intensities, as paresthesia did not increase from 150 to 200 mmHg (p>0.05). Conversely, pain responses showed significant differences across all pressure intensities (p<0.05) but not durations, as pain did not increase from 90 to 120 and from 120 to 150s (p>0.05). No interaction effects were found for either symptom. SC analysis showed no significant main or interaction effects. Intraclass correlation coefficients (ICCs) indicated moderate to good reliability for pain and paresthesia induction across different durations and intensities (ICC: 0.52-0.90), while SC showed poor to moderate reliability (ICC: 0.21-0.73). In conclusion, computerized cuff algometry seems to be an effective and reliable method for simultaneously inducing and assessing pain and paresthesia, revealing that these symptoms follow different patterns based on pressure duration and intensity.

physiology↗

bioRxiv2022

Spatial tuning in nociceptive processing is driven by attention

When the source of nociception expands across a body area, the experience of pain increases due to the spatial integration of nociceptive information. This well-established effect is called spatial summation of pain (SSp) and has been the subject of multiple investigations. Here, we used cold-induced SSp to investigate the effect of attention on the spatial tuning of nociceptive processing. Forty pain-free volunteers (N=40, 20 females) participated in this experiment. They took part in an SSp paradigm based on three hand immersions into cold water (5{degrees}C): Participants either immersed the ulnar segment ("a"), radial segment ("b") or both hand segments ("a+b") and provided overall pain ratings. In some trials based on "a+b" immersions, they were also asked to provide divided (i.e., first pain in "a" then in "b"; or reversed) and directed attention ratings (i.e., pain only in "a" or "b"). Results confirmed a clear SSp effect in which reported pain during immersions of "a" or "b" was less intense than pain during immersions of "a+b" (p<0.001). Data also confirmed that spatial tuning was altered. SSp was fully abolished when participants provided two ratings in a divided fashion (p<0.001). Furthermore, pain was significantly lower when attention was directed only to one segment ("a" OR "b") during "a+b" immersion (p<0.001). We conclude that spatial tuning is dynamically driven by attention as reflected in abolished SSp. Directed attention was sufficient to focus spatial tuning and abolish SSp. Results support the role of cognitive processes such as attention in spatial tuning. PerspectiveThis article presents experimental investigation of spatial tuning in pain and offers mechanistic insights of contiguous spatial summation of pain in healthy volunteers. Depending on how pain is evaluated in terms of attentional derivative (overall pain, directed, divided attention) the pain is reduced and spatial summation abolished.

neuroscience↗