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Hayley Bounds

@hayleybounds.bsky.social

180 followers 270 following 14 posts

Systems/computational neuroscience postdoc @ Columbia in the Losonczy and Fusi labs. Schmidt Science Fellow. Formerly Adesnik lab @ UC Berkeley.

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Hayley Bounds @hayleybounds.bsky.social · May 15

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).

Neuron @cp-neuron.bsky.social · May 15

Online now:

Network influence determines the impact of cortical ensembles on stimulus detection

By photostimulating specific visual cortical ensembles, Bounds et al. discovered that an ensemble’s impact on local neural activity, not its visual encoding properties, predicts its impact on stimulus detection. Their analysis reveals that mice use a generalizable, albeit suboptimal, perceptual readout strategy of summing all V1 activity to detect stimuli.

dlvr.it

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Reposted by Hayley Bounds

Matteo Carandini @carandinilab.net · Sep 3

The two key studies of the International Brain Laboratory @intlbrainlab.bsky.social are out today!

A brain-wide map of neural activity during complex behaviour
www.nature.com/articles/s41...

Brain-wide representations of prior information in mouse decision-making
www.nature.com/articles/s41...

A brain-wide map of neural activity during complex behaviour - Nature

The International Brain Laboratory presents a brain-wide electrophysiological map obtained from pooling data from 12 laboratories that performed the same standardized perceptual decision-making task i...

www.nature.com

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Sandra Romero Pinto @sromeropinto.bsky.social · Aug 13

My first paper with @naoshigeuchida.bsky.social is finally out in @natcomms.nature.com ! rdcu.be/eACGf

TL;DR: asymmetric learning rates can be induced by shifts in tonic dopamine giving rise to pessimistic/optimistic biases in agents or animals undergoing reinforcement learning .

Tonic dopamine and biases in value learning linked through a biologically inspired reinforcement learning model

Nature Communications - Accurate future predictions are essential for guiding behavior, and disruptions in this process are associated with psychiatric disorders. Here the authors show that changes...

rdcu.be

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Mora Ogando @moraogando.bsky.social · Aug 5

Thrilled to share our new Adesnik lab paper!!
Using holography in excitatory & inhibitory neurons, we reveal how a single cortical circuit can both complete and cancel predictable sensory activity, sharpening representations
📄https://www.biorxiv.org/content/10.1101/2025.08.02.668307v1
🧵

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Reposted by Hayley Bounds

carolinehaimerl.bsky.social @carolinehaimerl.bsky.social · Jul 29

When neurons change, but behavior doesn’t: Excitability changes driving representational drift

New preprint of work with Christian Machens: www.biorxiv.org/content/10.1...

Representational drift without synaptic plasticity

Neural computations support stable behavior despite relying on many dynamically changing biological processes. One such process is representational drift (RD), in which neurons' responses change over ...

www.biorxiv.org

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Hayley Bounds @hayleybounds.bsky.social · Aug 2

Certainly true! These two things are related but not the same. This is actually a bit of a misstatement in the article as in the study we don’t look at response strength but at neurons based on their visual information (measured by ROC) metrics and find that they do not appear to be weighted more.

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Dr Nick @nmwilkinson.bsky.social · Aug 2

Oh! Seems like a big deal, this. Makes sense too. Like, how would the rest of the brain know which neurons to sample, and if it did already know what the stimulus is, then it wouldn't need those neurons' signals to classify it.

The Transmitter @thetransmitter.bsky.social · Jul 31

Some neurons respond more strongly to visual stimuli than others. But the rest of the brain doesn’t prioritize signals from those neurons, according to a new study. Read more in this month’s Null and Noteworthy.

By @ldattaro.bsky.social

#neuroskyence

www.thetransmitter.org/null-and-not...

Null and Noteworthy: Downstream brain areas read visual cortex signals en masse in mice

The finding contradicts a theory that the regions prioritize neurons that are adept at identifying specific stimuli. Plus, a response to a study that questioned immune memory in astrocytes.

www.thetransmitter.org

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Hayley Bounds @hayleybounds.bsky.social · Aug 1

Thanks to @thetransmitter.bsky.social and @ldattaro.bsky.social for this coverage of our recent paper!

The Transmitter @thetransmitter.bsky.social · Jul 31

Null and Noteworthy: Downstream brain areas read visual cortex signals en masse in mice

The finding contradicts a theory that the regions prioritize neurons that are adept at identifying specific stimuli. Plus, a response to a study that questioned immune memory in astrocytes.

www.thetransmitter.org

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Mark Histed @markhisted.org · Jul 24

This is a simplistic but commonly-held view about how science actually works.

Doing rigorous& impactful science often means ignoring (some) null results.

Intermediate results, null and positive, arise on the way to a publishable contribution, and not all are perfectly rigorous.🧪#neuroscience 1/

John Holbein @johnholbein1.bsky.social · Jul 24

“just 68% of the 7,057 researchers whose work had produced null results had shared them in some form, and just 30% had tried to publish them in a journal.”

What a joke.

#NullEffectsMatter

www.nature.com/articles/d41...

Researchers value null results, but struggle to publish them

Survey finds that fear of reputational harm and a lack of support and publication platforms are among respondents’ key concerns.

www.nature.com

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Matteo Carandini @carandinilab.net · Jul 18

A new study led by @timothysit.bsky.social reveals that different layers of mouse V1 integrate visual and non-visual signals differently.

Activity is dominated by vision (or spontaneous fluctuations) in L2/3 and by movement in L5. This leads to different geometries.
www.biorxiv.org/content/10.1...

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Grace Lindsay @neurograce.bsky.social · Jul 7

Reminder that we still have time to fight this! This bill is being crafted & debated in the coming days and weeks. Organize NOW to do outreach and get people in your neighborhood contacting their reps. @standupforscience.bsky.social has resources. Instructions for Postcards-for-Science are here:

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talia jane ❤️‍🔥 @taliajane.bsky.social · Jun 21

Mahmoud Khalil is free.

a still of mahmoud khalil as he exited ice detention. he’s wearing a long sleeve khaki button up and a white and black keffiyeh wrapped around his neck. he’s got a big smile on his face and his fist raise in the air, defiant and proud.

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Maggie Astor @maggieastor.bsky.social · Jun 18

Breaking: The Trevor Project received a stop-work order last night on its contract with the national 988 suicide prevention hotline. The Trump administration is eliminating the option for LGBTQ callers to the hotline to press 3 and connect with someone who specializes in LGBTQ mental health.

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Matteo Carandini @carandinilab.net · Jun 9

The firing of neural populations is high-dim even if their subthreshold activity is low-dim! This work by @bio-emergent.bsky.social and @haydari.bsky.social shows how, with a solvable model, a data analysis technique, and data from mouse visual cortex: www.biorxiv.org/content/10.1...

High-dimensional neuronal activity from low-dimensional latent dynamics: a solvable model

Computation in recurrent networks of neurons has been hypothesized to occur at the level of low-dimensional latent dynamics, both in artificial systems and in the brain. This hypothesis seems at odds ...

www.biorxiv.org

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Aaron Milstein @neurosutras.bsky.social · May 27

New #NeuroAI #compneurosky preprint! To better understand how target-directed learning works in the brain, we sought to engineer an artificial neural network capable of solving complex image classification tasks that comprises only experimentally-supported biological building blocks. (1/15)

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Pailin Chiaranunt @phagocyticpai.bsky.social · May 23

We're now appreciating how the immune and nervous systems communicate across body & brain, and there's still more to explore!

Had a fun time co-writing this with some amazing immunologists and neuroscientists @nickmroz.bsky.social @arimolofskylab.bsky.social @annamolofskylab.bsky.social 😎🧠

Cross-regulation between the nervous system and type 2 immunity

The nervous and type 2 immune systems regulate each other via cytokines and neurotransmitters, suggesting previously unidentified therapeutic avenues.

www.science.org

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Hayley Bounds @hayleybounds.bsky.social · May 18

But also we try to be clearer on this in the paper but it’s hard in short form- we show that visual/task coding properties don’t determine read out but read out based on projection target is possible. I’d love to test that directly in the future!

Hayley Bounds @hayleybounds.bsky.social · May 18

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.

Hayley Bounds @hayleybounds.bsky.social · May 18

But I wouldn’t be surprised if we still find the strategy is a bit different than that predicted by decoders! Like Jin et al 2019 showing that mice don’t seem to use negative weights on anti tuned neurons in their read out for orientation discrimination, even though that’s probably helpful

Hayley Bounds @hayleybounds.bsky.social · May 18

I’d speculate I’d see the same in other discrimination tasks where averaging regardless of neural vis properties is viable. But different oris of equal contrast stimuli drive very similar average V1 activity, so that presumably needs different strategy. Marshel et al 2019 also supports this idea.

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Hayley Bounds @hayleybounds.bsky.social · May 17

I definitely don't think I would've gotten the same results in several common discrimination tasks (ie orientation discrimination). But, in addition to your results, Gauld et al's 2024 photostim results are also consistent with averaging occurring in discrim when the task is amenable to it.

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Hayley Bounds @hayleybounds.bsky.social · May 17

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

Hayley Bounds @hayleybounds.bsky.social · May 17

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

Reposted by Hayley Bounds

Qihong (Q) Lu @qlu.bsky.social · May 8

I’m thrilled to announce that I will start as a presidential assistant professor in Neuroscience at the City U of Hong Kong in Jan 2026!
I have RA, PhD, and postdoc positions available! Come work with me on neural network models + experiments on human memory!
RT appreciated!
(1/5)

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Shahab Bakhtiari @shahabbakht.bsky.social · May 17

These very cool findings match up perfectly with our human psychophysics data from this paper: jov.arvojournals.org/article.aspx...

Brains are fine using dumb (aka suboptimal) strategies when they can get away with it.

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Hayley Bounds @hayleybounds.bsky.social · May 15

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.

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