Coordinated yet asymmetric striatal neuromodulatory dynamics encode associative learning

The striatum integrates dopamine (DA) and acetylcholine (ACh) to shape learning and action, yet the principles governing their in vivo coordination remain unclear. Here we combine dual-color fiber photometry with low-dimensional manifold analysis to characterize DA-ACh interactions in the anterior dorsolateral striatum during associative learning. We find that both neuromodulators undergo learning-related plasticity but exhibit distinct temporal signatures. DA responses are fast and event-locked, whereas ACh shows broad, sustained modulation across behavioral epochs. Low-dimensional coordination between DA and ACh during cue-reward events robustly predicted learned trial states. By contrast, spontaneous lick-related activity was dominated by amplitude scaling and showed weaker low-dimensional structure, indicating that manifold organization preferentially encodes learned states rather than generic motor output. Granger causality analysis reveals a robust temporal asymmetry, with DA reliably predicting subsequent ACh fluctuations but not vice versa. These findings suggest that DA acts as a directional temporal scaffold organizing ACh within a shared neuromodulatory manifold, reframing DA and ACh not as independent channels but as a hierarchically coupled system for striatal computation.