Dynamic imbalances in cell-type-specific striatal ensembles reflect learned coupling between trajectory representations and locomotor dynamics

Basal ganglia models commonly propose that relative imbalances between direct and indirect pathway output shapes movement, but how such imbalances are expressed during behavior remains unclear. We simultaneously imaged identified direct-pathway and indirect-pathway spiny projection neurons (dSPNs and iSPNs) in dorsal striatum as mice locomoted through virtual visual environments for reward. Individual dSPNs and iSPNs encoded discrete locations within specific visual environments and, in a distance-based task, encoded distance traveled or elapsed time, revealing structured representations of goal-directed trajectories. At the population level, both pathways were broadly co-active and similarl