Thanks to our funders and to @alleninstitute.bsky.social for the open-access dataset which allowed us to investigate this question.

One possibility is that they are specialised for encoding optic flow (see Saleem 2020 www.sciencedirect.com/science/arti...).

We discuss other features of AM and PM that suggest their suitability for the encoding of locomotion-related optic flow in the discussion.

So why are medial HVAs selectively enhanced for visual speed encoding during locomotion?

Our results therefore reveal how a complex interplay of sensory input and ongoing behaviour differentially shapes the efficacy of sensory processing in mouse HVAs. They also highlight the importance of considering behaviour and context when ascribing functional specialisations to mouse HVAs.

This selective enhancement of medial HVAs during locomotion wasn’t generic, but specific to visual speed encoding - drifting gratings direction encoding changed non-selectively across mouse visual cortex.

We were also able to better decode visual speed from population activity in these same areas during locomotion, underlining that the enhancement of visual speed encoding during locomotion is specific to medial HVAs.

Remarkably, when we compared stationary and locomotion behavioural states we found that locomotion selectively enhanced visual speed tuning in medial HVAs AM and PM, along with V1 and LGN.

We next focused on how visual speed encoding changes between behavioural states. Previous research has shown that visual feature tuning tends to improve during locomotion in mouse V1, but whether such enhancements occur non-selectively across mouse visual cortex remains poorly understood.

We focused on how the mouse visual system encodes visual speed and discovered 4 classes of tuning across cortical and thalamic areas. We investigated the properties of these different tuning classes and how they varied between areas.