biostudies-literatureLiska JPNEI NIH HHSNINDS NIH HHSNational Institutes of HealthNIH HHSAir Force Office of Scientific ResearchNational Science FoundationRP87736https://www.ebi.ac.uk/biostudies/studies/S-EPMC11575896biostudies-literatureUnknown12When mice run, activity in their primary visual cortex (V1) is strongly modulated. This observation has altered conceptions of a brain region assumed to be a passive image processor. Extensive work has followed to dissect the circuits and functions of running-correlated modulation. However, it remains unclear whether visual processing in primates might similarly change during locomotion. We therefore measured V1 activity in marmosets while they viewed stimuli on a treadmill. In contrast to mouse, running-correlated modulations of marmoset V1 were small and tended to be slightly suppressive. Population-level analyses revealed trial-to-trial fluctuations of shared gain across V1 in both species, but while strongly correlated with running in mice, gain modulations were smaller and more often eLifeRunning modulates primate and rodent visual cortex differently.PMC11575896BRAIN Initiative U01-UF1NS116377K99EY032179-02FA9550-19-1-0357K99 EY032179NSC-FO 2123605UF1 NS116377Muthmann JORowley DPYates JHuk ACNguyen TTKButts DALiska JPfalseRunning modulates primate and rodent visual cortex differently.When mice run, activity in their primary visual cortex (V1) is strongly modulated. This observation has altered conceptions of a brain region assumed to be a passive image processor. Extensive work has followed to dissect the circuits and functions of running-correlated modulation. However, it remains unclear whether visual processing in primates might similarly change during locomotion. We therefore measured V1 activity in marmosets while they viewed stimuli on a treadmill. In contrast to mouse, running-correlated modulations of marmoset V1 were small and tended to be slightly suppressive. Population-level analyses revealed trial-to-trial fluctuations of shared gain across V1 in both species, but while strongly correlated with running in mice, gain modulations were smaller and more often 2024-01-01T00:00:00Z2024 Nov2025-04-04T20:38:25.546Z2025-04-04T20:38:25.546ZS-EPMC115758963956066010.7554/eLife.87736