Huge thanks to all the authors!!, especially @lamiaeadm.bsky.social who designed and built this powerful all-optical system, and to the great Adesnik Team!!

So WHY is the brain wired with a like-to-like inhibitory loop?
Stimulating co-tuned SSTs while showing their preferred visual input:
-Reduces evidence for flanking orientations (consistent with explaining away)
-Preserves evidence for correct orientation
-Boosts discriminability

In fact, directly activating co-tuned SST ensembles alone is sufficient to remove input-matching representations in the absence of visual input.

Feature completion can be explained by the well-known like-to-like PC-PC connectivity in V1, but where does the feature-specific suppression come from?
-PCs recruit co-tuned SSTs (not PVs)
-SSTs, in turn, suppress co-tuned PCs → a “like-to-like-to-like” inhibitory loop

Using all-optical physiology in awake mice we photostimulated orientation-tuned PC ensembles in V1 in the absence of visual input, and we found:
Small PC ensembles → dominant feature suppression
Large PC ensembles → dominant feature completion