Excited to share my PhD paper! In it, we use targeted 2-photon optogenetic stimulation to determine how V1 activity is read-out in a detection task. We found that network influence, not visual coding properties, predicted the impact of ensembles on behavior - contradicting our expectations (1/5). - ThreadSky

hayleybounds.bsky.social • 18 days ago

Excited to share my PhD paper! In it, we use targeted 2-photon optogenetic stimulation to determine how V1 activity is read-out in a detection task. We found that network influence, not visual coding properties, predicted the impact of ensembles on behavior - contradicting our expectations (1/5).

Reposted from Neuron

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ianoldenburg.bsky.social•17 days ago

Awesome work Hayley!!

hayleybounds.bsky.social•18 days ago

This is surprising because, although V1 responds monotonically to contrast, so an unweighted read out can solve contrast detection, more strongly weighting more visually sensitive neurons is much more optimal (2/5)

hayleybounds.bsky.social•18 days ago

If this more optimal strategy is used, photostimulating visually sensitive ensembles should more positively impact detection performance than photostimulating random ensembles. Using targeted optogenetics, we photostimulated ensembles with different visual sensitivity in behaving animals (3/5)

hayleybounds.bsky.social•18 days ago

We found that the visual sensitivity of photostimulated ensembles did not predict the change in behavior - instead the overall impact on network activity (both directly via photostimulation and indirectly via recurrent impacts) was strongly predictive of behavioral change (4/5)

hayleybounds.bsky.social•18 days ago

This argues that downstream regions summate V1 activity without preferentially weighting more informative neurons to make sensory decisions in this task. Why use a suboptimal strategy? Speculatively, this generalizable strategy may be better in unpredictable natural environs.

seanfw.bsky.social•16 days ago

How do you think this happens in the circuit? Only a small fraction of V1 neurons will project to any downstream area. So I imagine the summation happening, at least partially, within V1?

hayleybounds.bsky.social•15 days ago

Yeah this is an important point. Recurrent excitation in V1 could mean that neurons are recruiting more neurons and so they recruit neurons with all the important projection targets. I believe the great majority of L2/3 neurons connect to L5 which is an important output route.

jbarbosa.org•16 days ago

Beautiful thoughtprovoking work, congrats!

I am wondering, would you see the same thing if you look at PCA loadings: are neurons more correlated with global dynamics – regardless of their contribution to stimuli encoding – more relevant to behavior?

hayleybounds.bsky.social•16 days ago

Thanks! We did look at this a little. Generally PCA pulls out components related to visual or task variables so you get the same results. But I also ran PCA on only intertrial activity and didn’t see any link between weights and behavioral relevance

hayleybounds.bsky.social•16 days ago

Take that with a grain of salt though since this spontaneous dataset isn’t huge!

nmwilkinson.bsky.social•16 days ago

📌

haydari.bsky.social•16 days ago

So cool! Congrats :)

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