More running causes more ocular dominance plasticity in mouse primary visual cortex: new gated running wheel setup allows to quantify individual running behaviour of group-housed mice

Environmental enrichment boosts neuronal plasticity of standard-cage raised (SC) mice. Since it becomes increasingly more important to track individual mouse behaviours and its influence on brain plasticity, we designed a gated running wheel (gRW) setup allowing to correlate wheel running with neuronal plasticity, using the established paradigm of ocular dominance (OD)-plasticity after monocular deprivation (MD). After SC-rearing until adulthood (>P110), group-housed mice were transferred to gRW cages, that provided an additional running wheel compartment for tracking individual wheel activity via implanted RFID chips. Notably, individual running parameters varied enormously: mice ran from close to 0 to ∼20 km across the 7 days of gRW experience, with on average running 0-3.96 km in 0-3.85 h/d and running bouts lasting from <1 up to 10 min, while running at a speed of 6-26 cm/s. OD-plasticity in V1 after 7 days of MD in the gRW was visualized using intrinsic signal optical imaging, and compared to control gRW-mice without MD via calculation of an OD-index. Most, notably - while wheel running enabled OD-plasticity - individual running parameters correlated with individual OD-indices after MD: Mice running longer distances, for longer time, at higher speeds and with longer and more frequent bouts displayed more experience-dependent V1-plasticity. In turn, a composite measure of overall running wheel activity derived from principal component analysis of running parameters accounted for 65% of inter-individual variability of OD-index following MD. Together our study demonstrates that interindividual variability of running behaviour is high, and mice intrinsically motivated to run more show enhanced V1-plasticity, underscoring the huge importance of analysing individual behavioural parameters together with any measure of brain plasticity. End Graphical abstract With our newly developed gated running wheel setup, we observed a striking correlation between individual running activity, and a measure of experience dependent plasticity in mouse primary visual cortex. More running caused more plasticity: running speed, running distance, total running time, number of running bouts and bout duration all correlated with a measure of visual cortical plasticity, the ocular dominance index. Thus, our observations add to the growing body of evidence that individual behavioural choices strongly affect individual brain plasticity.