Lucas C Parra
@lcparra.bsky.social
580 followers 330 following 110 posts
NeuroAI, applied neuroscience, machine learning, brain stimulation, neural signals, medical imaging - physicist by training. parralab.org
Posts Media Videos Starter Packs
Reposted by Lucas C Parra
aoc.bsky.social
We believe healthcare is a right for every American.

But starting today, millions of people will be notified that they are being priced out of their insurance thanks to Republican policies.

Enough is enough. The GOP may shut down the government, but we will stand tall for YOU.
Reposted by Lucas C Parra
sciezgin.bsky.social
So flattering! Thanks @biophysicalsoc.bsky.social for this deeply meaningful award! All credit goes to my lab members and collaborators.
@scilifelab.se @ki.se
biophysicalsoc.bsky.social
Erdinc Sezgin to Receive 2026 Early Independent Career Award
www.biophysics.org/news-room/er...
lcparra.bsky.social
... unnamed White House official says ... "It will first apply in the upcoming lottery cycle for new applicants.".

This sounds like it won't apply to cap-exempt H1B for academia, or will it?

Chaos and arbitrary rules, again.

www.axios.com/2025/09/20/t...
Trump's new H-1B fee won't apply to existing visa holders, official says
The $100,000 fee for the highly prized visa is intended to boost jobs for U.S. workers.
www.axios.com
lcparra.bsky.social
Does anyone know if this affects cap-exempt H1-B at academic institutions?
Reposted by Lucas C Parra
rimaanabtawi.bsky.social
Fewer guns = fewer deaths
Simple fact.
We are the world outlier.
Reposted by Lucas C Parra
lcparra.bsky.social
And 93 of mine ...
gunnarblohm.bsky.social
They used 51 of my papers...
ryanestrada.com
Just a reminder to check for your name in this list of books that OpenAI trained from. If your name is there, they probably owe you several thousand dollars.

OpenAI cried that if everyone eligible author files, the company will go bankrupt, so I'm alerting every author I have ever spoken to.
Reposted by Lucas C Parra
Reposted by Lucas C Parra
davidho.bsky.social
The time between fucking around and finding out for messing with the climate and environment is long, and attribution is sometimes difficult. So conservative politicians have gotten away with appointing imbeciles to positions of power in these areas. However, no such luck for them in public health.
Opinion | Bernie Sanders: Kennedy Must Resign
www.nytimes.com
Reposted by Lucas C Parra
carlosbrody.bsky.social
This rule would have meant I couldn't do my Ph.D. in America.

I did do it in America. Became a professor. 12 thriving U.S. labs are now headed by trainees from my research lab. Like me, they are all working hard to enrich American knowledge and society.

With this self-harming rule, none of that.
crampell.bsky.social
Trump admin planning to change student visas from lasting for duration of academic program to fixed 4-yr term, and then much harder to renew
Could destroy US ability to attract global talent, particularly those seeking advanced degrees in STEM. The median time to complete a PhD is 5.7 yrs per NSF.
Trump Deals A New Immigration Blow To International Students
Trump officials have proposed a new rule limiting international students to fixed periods of entry, making a U.S. education more precarious.
www.forbes.com
Reposted by Lucas C Parra
Reposted by Lucas C Parra
agreco.bsky.social
Are top-down feedback connections enough for robust vision?

We found ConvRNN with top-down feedback exhibiting OOD robustness only when trained with dropout, revealing a dual mechanism for robust sensory coding

with @marco-d.bsky.social, Karl Friston, Giovanni Pezzulo & @siegellab.bsky.social

🧵👇
lcparra.bsky.social
I had totally missed this development of "fast weight programming" (FWP). This review makes a fascinating connection between recurrent networks and transformers with FWP right between the two. Supper interesting.
hritz.bsky.social
Fast weight programming and linear transformers: from machine learning to neurobiology arxiv.org/abs/2508.084...
Reposted by Lucas C Parra
aforli89.bsky.social
Our study is out in Nature!
Using wireless Neuropixels we recorded hippocampal activity in freely flying bats and uncovered replay and theta(less) sweeps, revealing striking differences from classic rodent models.

👉 www.nature.com/articles/s41...
Replay and representation dynamics in the hippocampus of freely flying bats - Nature
Nature - Replay and representation dynamics in the hippocampus of freely flying bats
www.nature.com
lcparra.bsky.social
This new paper on memory of stories makes perfect sense to me: we remember those topics better that get more time in the narrative.

Nice work.
alexanderhuth.bsky.social
New paper with @mujianing.bsky.social & @prestonlab.bsky.social! We propose a simple model for human memory of narratives: we uniformly sample incoming information at a constant rate. This explains behavioral data much better than variable-rate sampling triggered by event segmentation or surprisal.
biorxiv-neursci.bsky.social
Efficient uniform sampling explains non-uniform memory of narrative stories https://www.biorxiv.org/content/10.1101/2025.07.31.667952v1
Reposted by Lucas C Parra
rk70534.bsky.social
"The BBC World Service has compiled material on over 160 cases where children have been shot in Gaza, and found that in 95 cases the child was shot in the head or chest.

In most of these cases the victim was under 12 years old."

www.youtube.com/watch?v=TjP6...
Investigating the killings of children in Gaza | BBC News
YouTube video by BBC News
www.youtube.com
lcparra.bsky.social
Interestingly, they chose to keep the dynamic A constant. Friston et al. assume A to be modulated by the task. The assumption that the brain has (largely) constant dynamic is consistent with our findings in iEEG

elifesciences.org/articles/104...

We are finding the same in EEG. Preprint coming ...
lcparra.bsky.social
Nice work modeling behavior and EEG as dynamical systems. The State space model is similar to the "dynamical causal model" (without all the fantastical claims). Their code seems to work well in high dimensions, whereas DCM has only been used in small problems, despite both using the EM algorithm.
hritz.bsky.social
We put out this preprint a couple months ago, but I really wanted to replicate our findings before we went to publication.

At first, what we found was very confusing!

But when we dug in, it revealed a fascinating neural strategy for how we switch between tasks

doi.org/10.1101/2024.09.29.615736

🧵
Reposted by Lucas C Parra
bordergroves.bsky.social
The word “Research” is doing way too much work. We need separate words for “creating new verifiable knowledge” and “looking shit up on the internet”
Reposted by Lucas C Parra
oliviachristiano.bsky.social
How reliable is OPM-MEG, and how does it compare to other neuroimaging modalities? 🤔

In a new preprint with ‪@s-michelmann.bsky.social‬, we evaluate the reliability of OPM-MEG within & between individuals, and compare it to fMRI & iEEG during repeated movie viewing. 🧠

📄 doi.org/10.1101/2025...
Reliability and signal comparison of OPM-MEG, fMRI & iEEG in a repeated movie viewing paradigm
Optically pumped magnetometers (OPMs) offer a promising advancement in noninvasive neuroimaging via magnetoencephalography (MEG), but establishing their reliability and comparability to existing metho...
doi.org
lcparra.bsky.social
Here is another idea from biology on how to make ANNs learn more efficiently during continual learning. Adjust weights in first layers early in development [to learn shared representations] and keep higher layers plastic for longer [to learn new tasks].

www.biorxiv.org/content/10.1...