Robert Rosenbaum

Robert Rosenbaum

@robertrosenbaum.bsky.social

Associate Professor of Applied and Computational Mathematics and Statistics and Biological Sciences at U Notre Dame. Theoretically a Neuroscientist.

933 followers677 following74 posts

In other words: Plasticity rules like Oja's let us go beyond studying how synaptic plasticity in the brain can _match_ the performance of backprop. Now, we can study how synaptic plasticity can _beat_ backprop in challenging, but realistic learning scenarios.

We often forget how important careful weight initialization is for training neural nets because our software initializes them for us. Adding Oja's rule to backprop also eliminates the need for careful weight initialization.

In our new preprint, we dug deeper into this observation. Our motivation is that modern machine learning depends on lots of engineering hacks beyond pure backprop: gradients averaged over batches, batchnorm, momentum, etc. These hacks don't have clear, direct biological analogues.

In previous work on this question, we meta-learned linear combos of plasticity rules. In doing so, we noticed something intersting: One plasticity rule improved learning, but its weight updates weren't aligned with backprop's. It was doing something different. That rule is Oja's plasticity rule.

Robert Rosenbaum reposted

I made this figure panel size guide to avoid thinking about dimensions every time. Apparently this post is going to be a 🧵! So feel free to bookmark it and save some time of yours.

High-Dimensional Dynamics in Low-Dimensional Networks. New preprint with a former undergrad, Yue Wan. I'm not totally sure how to talk about these results. They're counterintuitive on the surface, seem somewhat obvious in hindsight, but then there's more to them when you dig deeper.

Somewhat old news here, but since I'm switching over from the other site: Happy to announce that my Computational Neuroscience textbook was published by MIT Press. The text and code is freely accessible: mitpress.mit.edu/978026254808... (click Open Access) drive.google.com/drive/folder... (1/n)

mitpress.mit.eduModeling Neural Circuits Made Simple with PythonAn accessible undergraduate textbook in computational neuroscience that provides an introduction to the mathematical and computational modeling of neurons an...

The main text covers a minimal thread of concepts needed to build up from ion channels to neural networks. The book assumes no background in biology, only a basic background in math (e.g., calculus and matrices). All other mathematical background is covered in an appendix. (3/n)

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