Neural correlates of licking behavior modulated by target position in the striatal matrix compartment

The striatum is a major cortical input site of the basal ganglia and plays a critical role in the control of orofacial movements such as licking. However, how striatal activity relates to the spatial features of licking behavior remains unclear. In this study, we examined whether neural activity in the striatal matrix and striosomal compartments is associated with the spatial position of a licking target during an operant task. Head-fixed mice performed a licking task in which the target positions were varied across three spatial dimensions. Using fiber photometry in Calb1-IRES-Cre and Pdyn-IRES-Cre mice, we recorded calcium signals from matrix and striosomal neurons. Associations between neural activity, target position, and behavioral variables were quantified using linear mixed-effects modeling with cross-validation. Matrix activity prior to licking onset was primarily associated with the dorsal-ventral target position and reaction time. During licking, matrix activity was modulated by anterior-posterior and medial-lateral positions, independent of reaction time and lick count. In contrast, striosomal activity during licking was predominantly associated with the dorsal-ventral position. These findings demonstrate that neural matrix activity is systematically associated with spatial features of licking behavior, with distinct contributions before and during movement. Our results suggest that striatal matrix circuits provide task-relevant spatial signals for the control of orofacial actions. Significant StatementWe show that neural activity in the striatal matrix is associated with the three-dimensional position of a licking target during an operant task. Activity prior to licking onset reflects dorsal-ventral position, whereas activity during licking is modulated by the anterior-posterior and medial-lateral positions. These findings indicate that matrix activity represents spatial aspects of licking behavior, supporting a role for the striatum in integrating motor execution with task-specific spatial information and pointing to the matrix compartment as a substrate for transforming spatial coordinates into action-specific motor commands.