Yawaka, Y. | Search bioRxiv

bioRxiv2026

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.

neuroscience↗

bioRxiv2025

Neural responses prior to licking onset in the striatal matrix compartment in mice

Licking is a continuous tongue thrust observed during drinking in rodents and humans and is often studied as an essential tongue movement for feeding and swallowing. The striatum, a component of the basal ganglia, plays a critical role in licking onset; however, it is unclear how the two compartments of the striatum--the matrix and striosomes--contribute to the control of licking onset. In this study, we used male and female transgenic mice that selectively expressed Cre recombinase in matrix or striosome neurons and subjected them to operant conditioning based on licking of a spout, during which neuronal activity in both compartments was measured using fiber photometry. Only matrix neurons showed responses prior to licking onset. In addition, the matrix neural response before licking onset was larger when mice licked a spout ipsilateral to the recording hemisphere of the brain than that observed when licking the contralateral spout. This response was observed similarly in mice conditioned to receive a reward regularly and those conditioned to receive a reward randomly, suggesting that the response was unrelated to whether the reward was predictable or unpredictable. Matrix neural activity was negatively correlated with the number of licks during the water intake behavior following the first lick. These findings suggest that matrix neurons are involved in the preparatory process for licking onset as well as in the regulation of licking frequency during water intake. Significant StatementThis study demonstrated that during the expression of operant conditioning behaviors based on licking, striatal matrix neurons showed responses prior to licking onset. Additionally, these responses were larger when the mouse licked the spout ipsilateral to the brain hemisphere undergoing recording than when a spout in the contralateral direction was licked. This result was also true for mice conditioned using either regular or random reward conditions. Additionally, the number of licks during water ingestion behavior following the initial lick was negatively correlated with matrix neuron activity. These changes in matrix neuron activity are suggested to be involved in the preparatory process for licking onset, independent of reward prediction, and in the regulation of licking frequency during drinking.

neuroscience↗