Cognition and Computation 🧠 Tech enjoyer 💻
🥝➡️🦘
PhD candidate in Cog/Comp Neuroscience at The University of Queensland 🧠
Studying how the brain leverages experience to support sensory processing and decision-making under uncertainty.
Tim Gastrell
6/n
I thought this result was quite surprising since it cuts against the grain of popular predictive processing narratives and suggests task priors are doing more for the maintenance and transformation of sensory representations into action than for sensory encoding per se.
4/n
How does this bias emerge?
Recent work suggests task priors might accelerate evidence accumulation by directly enhancing early neural representations of more likely stimuli.
We were able to characterize these neural representations using EEG recorded during the task. 🧠
Results next!
5/n
Inverted encoding models showed strong effects of motion coherence on representational fidelity during stimulus observation which carried over into the response period (top).
Priors also enhanced stimulus representation (bottom), but only in the response period once the stimulus was gone! 🤯
fin.
If you made it this far, thanks for reading!
There's loads more in the paper if you like what you see.
I'm really keen to hear what people think so don't be shy and leave a reply/shoot me a dm.
www.biorxiv.org/content/10.6...
2/n
Participants made continuous decisions about the direction of a dot-motion stimulus with varying levels of coherence. We manipulated prior expectation by sampling the target directions from von Mises distributions whose location and concentration parameters varied each block.
3/n
Estimation behaviour followed the textbook Bayesian pattern:
Responses were biased towards expected motion directions and the magnitude of bias scaled with the relative precision of the stimulus and the prior. (panel C)
Weak stimulus + strong informative prior = biggest bias.
🏰 New preprint! 🏰
(w/ the excellent @neuronomist.bsky.social & Prof. Jason Mattingley)
For my PhD I've been using EEG, psychophysics and modelling to explore how the brain uses uncertainty to balance sensory information against expectations about what's out there.
🧵1/n
Late Integration of Prior Expectations During Precision Weighted Perceptual Decisions https://www.biorxiv.org/content/10.64898/2026.04.13.718329v1
