Modality-Specific Modulation of Temperature Representations in the Spinal Cord after Injury.

Different types of tissue injury, such as inflammatory and neuropathic conditions, cause modality-specific alternations on temperature perception. There are profound changes in peripheral sensory neurons after injury, but how patterned neuronal activities in the CNS encode injury-induced sensitization to temperature stimuli is largely unknown. Using in vivo calcium imaging and mouse genetics, we show that formalin- and prostaglandin E2-induced inflammation dramatically increase spinal responses to heating and decrease responses to cooling in male and female mice. The reduction of cold response is largely eliminated on ablation of TRPV1-expressing primary sensory neurons, indicating a crossover inhibition of cold response from the hyperactive heat inputs in the spinal cord. Interestingly, chemotherapy medication oxaliplatin can rapidly increase spinal responses to cooling and suppress responses to heating. Together, our results suggest a push-pull mechanism in processing cold and heat inputs and reveal a synergic mechanism to shift thermosensation after injury.SIGNIFICANCE STATEMENT In this paper, we combine our novel in vivo spinal cord two-photon calcium imaging, mouse genetics, and persistent pain models to study how tissue injury alters the sensation of temperature. We discover modality-specific changes of spinal temperature responses in different models of injury. Chemotherapy medication oxaliplatin leads to cold hypersensitivity and heat hyposensitivity. By contrast, inflammation increases heat sensitivity and decreases cold sensitivity. This decrease in cold sensitivity results from the stronger crossover inhibition from the hyperactive heat inputs. Our work reveals the bidirectional change of thermosensitivity by injury and suggests that the crossover inhibitory circuit underlies the shifted thermosensation, providing a mechanism to the biased perception toward a unique thermal modality that was observed clinically in chronic pain patients.

Psychometric Evaluation of the Caregiver Burden Inventory in Children and Adolescents With PANS.

Objectives: To establish the psychometric properties of the Caregiver Burden Inventory (CBI) in patients with Pediatric Acute-onset Neuropsychiatric Syndrome (PANS), which is characterized by the abrupt onset of obsessive-compulsive disorder and/or restricted eating and at least two additional psychiatric symptoms. Parents of patients with PANS have reported high caregiver burden. However, no validated instrument of burden exists for this population. Methods: Study took place at a community-based PANS clinic where the CBI is administered as part of routine clinical care. The first CBI available during an active disease flare was analyzed (N =104). Construct validity was evaluated within a confirmatory factor analytic framework. Associations between the CBI and patient/family characteristics were explored, and preliminary normative data for this population are presented. Results: Item-factor loadings were strong, and the overall fit of the model was good (root mean square error of approximation = .061). Strict/metric measurement invariance was demonstrated across age. The mean Total Score in this sample was 36.72 ± 19.84 (interquartile range 19-53). Total Scores on the CBI were significantly elevated for parents of children who switched schools because of their illness (Cohen's d = 0.75, 95% confidence interval [CI] 0.28-1.22) and for those who had reduced work hours to accommodate the child's illness (Cohen's d = 0.65, 95% CI 0.10-1.20). However, in this relatively high-status sample, socioeconomic variables did not predict Total Scores. Conclusions: Parents of patients with PANS experience high caregiver burden. The CBI may be confidently used to assess caregiver burden in this population.