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

Abstract 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. Competing Interest Statement The authors have declared no competing interest. Footnotes The updated manuscript has been thoroughly revised to include more detailed analysis of wheel activity in our newly established gated running wheel setup from mice older than postnatal day 110, and their respective correlation with ocular dominance plasticity. Since data from mice aged between P50-110 was less conclusive, in particular concerning the correlation of wheel activity with ocular dominance plasticity, we have removed the data from this manuscript.