Do people with acute low back pain have an attentional bias to threat-related words?

Objectives It has been hypothesised that attentional bias to environmental threats can contribute to persistent pain. It is unclear whether people with acute low back pain (LBP) have an attentional bias to environmental threats. We investigated if attentional bias of threat related words is different in people with acute LBP and pain-free controls. Methods People with acute LBP and pain-free people completed a free viewing eye tracking task. Participants were simultaneously presented with two words, a threat related word and a neutral control word. Threat related words were general threat, affective pain and sensory pain. We conducted linear mixed models to detect differences between acute LBP and pain-free participants on five eye tracking outcome measures (dwell time, first fixation, latency to first fixation, first run dwell time and number of fixations). We calculated absolute reliability, (standard error of measure), and relative reliability (intraclass correlation coefficients [ICC 2,1]) for each eye tracking outcome measures. Results We recruited 65 people with acute LBP and 65 pain-free controls. Participants with acute LBP had a higher proportion of fixations towards the affective pain words (M=0.5009, 95% CI=0.4941, 0.5076) than the pain-free controls had (M=0.4908, 95% CI=0.4836, 0.4979), mean between group difference = −0.0101, 95% CI [−0.0198, −0.0004], p=0.0422. There was no difference between acute LBP and pain-free controls for the remaining eye tracking outcome measures (all p>0.05). The only outcome measure that had an ICC of more than 0.7 was the latency to first fixation (affective pain words ICC=0.73, general threat words ICC=0.72). Conclusions When compared with pain-free controls, people with acute LBP looked more often at affective pain words relative to neutral control words. This may indicate a form of engagement bias for people with acute LBP. Attentional bias was not consistent across outcome measures or word groups. Further research is needed to investigate the potential role of attentional bias in the development of persistent pain.

Two birds with one stone.–Addressing depressive symptoms, emotional tension and worry improves tinnitus-related distress and affective pain perceptions in patients with chronic tinnitus

Background Psychological factors link the co-occurrence of tinnitus-related distress and pain perceptions in patients with chronic tinnitus. Objective This study examines, if treatment-related changes in these factors ameliorate both tinnitus-related distress and pain perceptions in a sample of patients with chronic tinnitus. Methods N = 1238 patients with chronic tinnitus provided pre- and post-treatment ratings of tinnitus-related distress and affective or sensory pain perceptions alongside measures of depressive symptoms and perceived stress. Treatment comprised an intensive tinnitus-specific multimodal treatment program. Using serial indirect-effects analyses, we examined association patterns between baseline values and change rates of those variables that were found to respond to treatment. Results Small effect sizes emerged for changes in tinnitus-related distress, affective (but not sensory) pain perceptions, depressive symptoms, emotional tension and worry. At pre- or post-treatment respectively, baseline values and change rates intercorrelated. Across timepoints, (1) baseline tinnitus-related distress and affective pain perceptions were positively associated with improvements in tinnitus-related distress, affective pain perceptions and depressive symptoms. (2) Baseline depressive symptoms or emotional tension mediated positive associations between baseline tinnitus-related distress and improvement in affective pain perceptions. (3) Change in depressive symptoms mediated the effect of baseline tinnitus-related distress on change in affective pain perceptions–partly through associated change in emotional tension or worry. Mood-independent aspects of emotional tension were negatively associated with improvement in affective pain perceptions. Conclusions Depressive symptoms, emotional tension and worry emerge as key predictors of treatment response and transdiagnostic treatment targets for alleviating tinnitus-related distress and functionally associated affective pain perceptions.

Unified neural pathways that gate affective pain and multisensory innate threat signals to the amygdala

Perception of aversive sensory stimuli such as pain and innate threat cues is essential for animal survival. The amygdala is critical for aversive sensory perception, and it has been suggested that multiple parallel pathways independently relay aversive cues from each sensory modality to the amygdala. However, a convergent pathway that relays multisensory aversive cues to the amygdala has not been identified. Here, we report that neurons expressing calcitonin gene-related peptide (CGRP) in the parvocellular subparafasicular thalamic nucleus (SPFp) are necessary and sufficient for affective-motivational pain perception by forming a spino-thalamo-amygdaloid pain pathway. In addition, we find that this thalamic CGRP pain pathway, together with well-known parabrachio-amygdaloid CGRP pain pathway, relays multisensory innate threat cues to the amygdala. The discovery of unified pathways that collectively gate aversive sensory stimuli from all sensory modalities may provide critical circuit-based insights for developing therapeutic interventions for affective pain- and innate fear-related disorders.

Unified neural pathways that gate affective pain and multisensory innate threat signals to the amygdala

Perception of aversive sensory stimuli such as pain and innate threat cues is essential for animal survival. The amygdala is critical for aversive sensory perception, and it has been suggested that multiple parallel pathways independently relay aversive cues from each sensory modality to the amygdala. However, a convergent pathway that relays multisensory aversive cues to the amygdala has not been identified. Here, we report that neurons expressing calcitonin gene-related peptide (CGRP) in the parvocellular subparafasicular thalamic nucleus (SPFp) are necessary and sufficient for affective-motivational pain perception by forming a spino-thalamo-amygdaloid pain pathway. In addition, we find that this thalamic CGRP pain pathway, together with well-known parabrachio-amygdaloid CGRP pain pathway, is critical for the perception of multisensory innate threat cues. The discovery of unified pathways that collectively gate aversive sensory stimuli from all sensory modalities may provide critical circuit-based insights for developing therapeutic interventions for affective pain- and innate fear-related disorders.