Structure of activity in multiregion recurrent neural networks | PNAS Neural circuits comprise multiple interconnected regions, each with complex dynamics. The interplay between local and global activity is thought to...

(1/23) In addition to the new Lady Gaga album "Mayhem," my paper with Manuel Beiran, "Structure of activity in multiregion recurrent neural networks," has been published today.

PNAS link: www.pnas.org/doi/10.1073/...

(see dclark.io for PDF)

An explainer thread...

Harvard Will Not Comply With a List of Trump Administration Demands Federal officials said Harvard must enact “merit-based reform” in hiring and admissions, among other things. Harvard called the demands unlawful.

Yay Harvard!!!!!!! Well done! Other universities should do the same.
www.nytimes.com/2025/04/14/u...

Data-for-good rapid response team I'm collecting people with data science skills who may want to hear about sporadic opportunities to use their skills for good on short projects. Project themes will center on topics I am connected wit...

I'm organizing a "Data for Good Rapid Response Team", i.e. a set of people who can be mobilized to work on short data science projects to help various groups and organizations. Sign up here if this is of interest to you, and please share with others with data science skills.

Institut Pasteur decides to leave X The Institut Pasteur, a research organization which for more than 130 years has been committed to tackling infectious diseases, sharing knowledge and defending science, has decided to leave X because ...

The Institut Pasteur has decided to leave X (formerly Twitter) to join BlueSky! 🦋
The Institut Pasteur made this decision due to several serious issues observed on the X platform since its acquisition. Join us here to continue advocating for science. www.pasteur.fr/en/home/pres...

Praising Pozzo Let’s, for chrissake, press pause on valorizing CEOs.

Good piece on the horrors of a society that valorizes CEOs
open.substack.com/pub/persuasi...

Most neurons in mouse cortex defy functional categories The majority of cells in the cerebral cortex are unspecialized, according to an unpublished analysis—and scientists need to take care in naming neurons, the researchers warn.

Excited to see @thetransmitter.bsky.social feature our preprint on how the neural code changes across the cortical hierarchy! A multi-region perspective on categorical selectivity 🧱 and geometric dimensionality 📐
Blueprint thread coming soon— after I am done with panettone digestion 🥮!

Great material here! ✨

What papers do you like that demonstrate the use of 'orthogonal subspaces' for encoding information in neural populations? #neuroskyence #compneuro #neuroAI

Network dynamics underlying OFF responses in the auditory cortex Computational modeling demonstrates that population dynamics of neural calcium activity following stimulus offset are consistent with a network mechanism based on recurrent interactions.

We published this a couple of years ago 🙃
elifesciences.org/articles/53151
Population responses in AC across a range of stimuli explored orthogonal subspaces.

(We found it convenient to apply dim. red. before computing the angles to avoid measuring too small angles in shared low-var dimensions)

I would think in Xie et al. the cosines are ranked so that cos(θ1)>cos(θ2) (not stated explicitly). Then cos(θ1) is the first (=max) singular value of the matrix Va.T*Vb, and θ1 the first principal angle.

Equations for different RNN update rules. Equation 1 has a linear decay term plus a term with nonlinearity applied to summed inputs (sum all inputs - recurrent, external, bias). Eq 2 is its discretized form. Equation 3 has linearized dynamics of rnn state x, with a pointwise nonlinearity applied only to the recurrent input, that is, W_rec phi(x). Equation 4 is the same as eq 3 for hidden state or potential x, but the firing rates are additionally obtained after applying the nonlinearity to the hidden state.

Comp #Neuroskyence hivemind - I've noticed multiple eqs for RNN dynamics that vary in interpretation and implications due to placement of nonlinearity. Similar mixture in theory papers... @loradrian.bsky.social @jbarbosa.org @bio-emergent.bsky.social @matthijspals.bsky.social @kenmiller.bsky.social

A screenshot of a paper on bioarxiv illustrating the lack of blue sky share button!

Would you like to see @biorxivpreprint.bsky.social add a share to blue sky button?! I know I would! Share this post to let @richardsever.bsky.social @erictopol.bsky.social and others at bioarxiv know!

Hi 👋 I would love to be added as well! Thanks!

Open letter of psychologists and neuroscientists for peace in the Middle East We, psychologists and neuroscientists from around the world, call the international community to urgently put pressure towards an immediate ceasefire in Israel, Palestine and Lebanon, to demand that t...

Psychologists and neuroscientists are calling for international pressure towards immediate ceasefire in Israel, Palestine & Lebanon, respect for international humanitarian law, end of the occupation, and release of all hostages.

Read & join us by signing here: tinyurl.com/PsychLetter