RUNNING ENHANCES VISUAL CODING IN STRIATAL NEURONS

The striatum is widely regarded as the principal input nucleus of the basal ganglia, where sensory information is integrated to guide motor actions. Recent evidence indicates that the dorsomedial striatum (DMS) receives functional projections from the visual cortex. Besides, we previously showed that the DMS encodes visual stimuli at both single-neuron and population levels during stillness. Notably, running modulates visual responses in the DMS, consistent with reports from the visual cortex. Despite this, it remains unknown how locomotion alters neural dynamics and coding across distinct neuronal subtypes in the DMS.
Here, we investigated if specific groups of DMS neurons differentially modify their visual dynamics and encoding during running. We recorded striatal units during the presentation of visually oriented drifting gratings and monitored running in naive mice; we found that visual responses in DMS are modulated by running. Notably, running enhanced visually evoked responses and increased orientation selectivity at both single-neuron and population levels. We further observed that visual responses were modulated by running across multiple neuronal subtypes in the DMS, including fast-spiking interneurons, but orientation coding was mainly increased over striatal projection neurons.
In conclusion, visual responses are enhanced in striatal neurons during running, dynamically reshaping neural activity across multiple processing levels and strengthening population coding. These findings suggest that the integration of visual and locomotor signals would facilitate visually guided motor actions within the basal ganglia.