Probing Selectivity and Tolerance with Optimized Dynamic Stimuli in a Foundation Model of the Mouse Visual Cortex

Selectivity and tolerance are fundamental response properties of visual systems. Selectivity describes how concentrated responses are across a stimulus set, whereas tolerance describes response preservation under a specified stimulus transformation. Comparing these properties across visual areas with a common dynamic stimulus protocol remains difficult when reference stimuli are restricted to predefined stimulus families. We analyze the MICrONS-adapted instance of a pretrained video-response foundation model as an in silico hypothesis generator. For each of 104,171 model readouts, we synthesize a most exciting dynamic input (MEDI), a short video optimized in a generative latent space. Compared with static stimuli, MEDIs contain temporal structure, enabling temporal transformations such as reversal and speed resampling. The readout-by-MEDI matrix shows positive within-model-area enrichment, while MEDI-set stimulus selectivity is the highest in model primary visual cortex (V1) and the lowest in model rostrolateral area (RL), with model lateromedial area (LM) and model anterolateral area (AL) intermediate; this pattern is not a simple monotonic progression along the established V1$\to$LM/RL$\to$AL hierarchy. Transforming each readout's own MEDI reveals transformation-specific tolerance: model RL retains relatively more response under strong spatial transformations, whereas model V1 retains relatively more under slow-down and relatively less under strong speed-up. Across transformations, tolerance does not show a single consistent area ordering. Selectivity and tolerance are negatively associated at selected transformation strengths, but the magnitude of this association depends on transformation and parameter rather than defining a single universal axis. The results revealed profound properties of different populations of readouts of the foundation model and provided experimentally testable predictions for the corresponding visual areas.