Condylar Position-Dependent Cerebellar Connectivity Changes in Painful Temporomandibular Disorder: A Brief Report

The cerebellum contributes to sensory, cognitive, emotional, and pain-modulatory processes beyond motor coordination. In temporomandibular disorders (TMD), alterations in spontaneous cerebellar neural activity and strengthened functional connectivity with limbic structures have been reported, suggesting involvement of central neuroplastic mechanisms. Mandibular displacement and occlusal imbalance may further modulate brain networks related to motor regulation, sensory integration, and pain-related emotional processing. In this study, magnetic resonance imaging(MRI) and diffusion tensor imaging(DTI) was used to examine cerebellar connectivity across different mandibular positions in a patient with painful TMD. Functional MRI and diffusion tensor imaging were acquired in three conditions: centric occlusion, centric relation, and stabilization splint. Cerebellar regions of interest were defined using SUIT parcellation, and position-dependent structural–functional connectivity was assessed using diffusion-based tractography and Δ-metrics (Δ = MNI − COUNT). No measurable cerebellar connectivity was detected in the centric occlusion condition. In contrast, both centric relation and splint positions demonstrated heterogeneous cerebellar connectivity patterns with substantial variability (centric relation: mean Δ 43.64, SD 101.48; splint: mean Δ 47.32, SD 106.89). Similarity between centric relation and splint connectivity profiles was low (r = 0.28; cosine similarity = 0.39), while large Euclidean distance and mean absolute difference values indicated marked divergence in network organization. These findings indicate that mandibular position is associated with distinct cerebellar connectivity patterns in painful TMD, consistent with position-dependent neuroplastic adaptation. Integration of functional and diffusion MRI may help to characterize central nervous system involvement in TMD and support the development of individualized therapeutic strategies.