Population dimensionality and timescale organization in mouse V1 under grating and natural movie stimulation

How does the complexity of neural population activity relate to how long its patterns persist? We addressed this question using primary visual cortex recordings from 26 mice (23 male and female) viewing drifting gratings and a natural movie. We analyzed single-trial responses at three temporal resolutions, measuring effective dimensionality and estimating population decay timescales with linear dynamical models. Movie responses had higher dimensionality and longer mean timescales than grating responses. Across recordings, dimensionality and mean timescale showed no consistent association within conditions or in their stimulus-driven changes, although movie responses showed a tentative negative association at the finest resolution (20 ms). Higher-dimensional movie responses nevertheless tended to show flatter log-timescale spectra across resolutions, while estimated correlations with slower and faster timescales varied between the finest and coarser resolutions (50 ms and 100 ms). These cross-session associations did not survive correction for multiple comparisons and remain exploratory. These findings highlight complementary geometric and temporal aspects of cortical responses and the value of examining both average persistence and the distribution of timescales. Significance Statement How does the diversity of neural activity patterns relate to their persistence over time? In mouse visual cortex, movie responses showed higher dimensionality and longer average decay times than grating responses. Across recordings, dimensionality and mean decay time showed no consistent relationship, with a tentative negative association in movie responses at 20-ms resolution. Exploratory movie analyses suggested that dimensionality may relate to the organization of slower and faster timescales: their association patterns varied across resolutions, while their relative separation tended to decrease at higher dimensionality. These findings highlight complementary geometric and temporal aspects of cortical responses and the value of examining both average persistence and the distribution of timescales.