Activity in primate visual areas is modulated during running

Introduction: Running roughly doubles activity in mouse V1, acting as a ~2x gain change (Niell & Stryker, 2010). We recently tested whether these profound modulations of V1 activity are also present in primate, by recording responses in foveal V1 while marmosets running on a treadmill viewed visual stimuli. We found only modest modulations, with hints of suppression. However, whether running affects peripheral representations and/or later visual areas remains unknown. Methods: Following our recent work (Liska, Rowley, et al., 2023), we presented drifting gratings of various orientations to three marmosets while they were perched on a treadmill. Using Neuropixels probes, we recorded from the foveal and peripheral representations of V1, as well as from V2 and MT. Results: We tested whether baseline activity and visually-driven responses were different during running versus not running. In foveal V1, we replicated our finding of little-to-no running effect. However, in the peripheral representation of V1, activity was higher during running in both stimulus viewing and blank periods. Running:Stationary firing rate ratio was 1.196 during stimulus viewing ([1.126, 1.265], 95% CI, p=1.8e-6, 63 cells) and 1.399 during blanks ([1.312, 1.477], p=2e-10). V2 activity was even more strongly modulated during stimulus viewing (1.252, [1.173, 1.351], p = 0.00016 , 26 cells) and during blanks (1.676, [1.416, 1.757], p = 0.00014). Saccade frequency and amplitudes did not differ strongly between conditions, arguing against these modulations arising from different patterns of eye movements when running. In MT, responses were not significantly affected by running (mean firing rate ratio of 1.032 [0.960, 1.109], 77 cells). Conclusion: Although primate foveal V1 is not much affected by running, peripheral V1 and V2 show clear running-correlated modulations. This forms a connection with the striking results found in mice, and calls for a comprehensive dissection of potential modulatory sources and effects.