Date of Award

Summer 2025

Document Type

Open Access Dissertation

Department

Exercise Science

First Advisor

Sheri p. Silfies

Abstract

In persons with chronic pain, fear or anxiety related to movement is a well-established model under the biopsychosocial framework that explains in part, the chronicity of symptoms commonly reported by individuals with chronic low back pain (cLBP). This dissertation aimed to further understand the link between the context-dependent emotion network in the brain and movement in two separate studies using brain functional MRI and autonomic nervous system indices. Aim 1sought to investigate the brain functional connectivity linking brain regions involved in context-dependent emotion and movement while cLBP participants moved their back inside the scanner by performing a modified trunk bridging task. Aim 2 involved recording autonomic nervous system responses (heart rate variability, skin conductance, and respiratory rate) while the cLBP participants visualized daily activities involving back movement. In Aim 1, during left and bilateral bridging tasks, we identified an altered functional connectivity (uncorrected false discovery rate) between several cortical context-dependent emotional and cortical or cerebellar sensorimotor brain regions in individuals with cLBP. Findings of an association between lower connectivity and clinical measures of pain modulation, and pain-related disability suggest less engagement of self-referential and cognitive control to sensorimotor networks. A lower functional connectivity of the insula to the SMA, was associated with clinical measures of hypervigilance that may explain a disintegration of the emotional awareness and motor planning network among individuals with cLBP. Aim 2 captured heart rate variability, skin conductance, and respiratory rate while the individuals with cLBP visualized themselves completing back movement that they perceived as either less harmful or more harmful when viewing images demonstrating back stresses. For this aim, we updated the functional tasks that stress the back and created a more ethnically and racially diverse PHODA picture series. Autonomic responses associated with visualization of daily back movements were used to understand the context-specific nature of anxiety. In contrast to our hypothesis, we did not observe any between-group differences or a task interaction effect in autonomic nervous system indices or subjective measures of anxiety between cLBP and HCs. However, exploratory analyses revealed a smaller increase in sympathetic response, lower parasympathetic response, and a slight dominance of sympathetic response over parasympathetic responses during the less-harmful block of PHODA images, evident immediately after nature visualization. These studies provide preliminary evidence of support for central nervous system changes in persons with cLBP that suggest a role for fear or anxiety related to trunk movements.

Rights

© 2025, Pradeep Kumar Sahu

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