In a recent study, researchers aimed to understand why tardive dyskinesia (TD) often exhibits orofacial symptoms, while also exploring the neural network involved. The researchers conducted graph analysis on a high-level cortico-striato-thalamo-cortical network and found a connectivity bottleneck, suggesting a vulnerability in the substantia nigra pars reticulata (SNr). They also analyzed published data on rodent neural networks and discovered that the SNr exhibited a heterogeneous connectivity structure, with increased local connections to orofacial regions, indicating potential compensatory pathways; however, extensive damage to the SNr might limit these compensatory mechanisms. Identifying vulnerable structures in TD is crucial for targeted therapeutic interventions. The study concludes that the SNr plays a significant role, and interventions focused on this area, possibly through the subthalamic nucleus, could help reduce repetitive orofacial movements. These findings align with previous research showing a higher involvement of SNr neurons in orofacial movements compared with limb movements, providing insight into the prevalence of orolingual movements in TD.

Reference: Szalisznyó K, Silverstein DN. Why Does Tardive Dyskinesia Have Oro-facial Predominance? A Network Analysis. Brain Topogr. 2023;36(1):99-105. doi: 10.1007/s10548-022-00931-y.