Elisabeth Parés Pujolràs

Our #sEEG study is now published in Nature Communications: rdcu.be/eIkoG! 🧠
Key finding: We discovered neural evidence accumulation for visual perception that's independent of report preparation—recorded from >3000 channels across 3 experiments!
#Neuroscience #Consciousness #OpenAccess

Overall, our results highlight how prominent neural decision signals may take different shapes in different contexts, and how probing them using tasks that depart from conventional ones can provide important insights into their functional roles. Thanks for reading this far!

Dissociable encoding of evolving beliefs and momentary belief updates in distinct neural decision signals - Nature Communications People are capable of making near-optimal decisions in volatile, changing environments. Here, the authors show how two neural decision signals encode distinct aspects of the belief updating process underpinning such adaptive decisions.

These results align with recent work in an expanded judgement task under volatility, where the CPP following individual tokens shows transient evoked activities that scale with context-optimal belief updates:
www.nature.com/articles/s41...

Model-based simulated EEG data

A simple bounded accumulation model could capture the key behavioural patterns in our data, and model-based simulations were able to reproduce the condition-specific profiles of the neural data (CPP & MBL) following each pulse 👇

Our participants sometimes terminated decisions early, tending to use the second pulse less than the first one, and CPP amplitudes following each pulse reflected this differential weight on choice (i.e. small CPP, small weight on choice), also capturing condition-specific differences in the effect.

This transient pattern of activity stands in contrast to motor beta lateralisation (MBL), which keeps track of the total sum of accumulated evidence throughout the intervals between pulses and until response.

We show that when noisy evidence for a single decision comes in temporally separate pulses, the centroparietal positivity (CPP) tracks multiple rounds of evidence accumulation, falling back down to baseline during the intervals in between pulses when no relevant info is presented.

Check out our reviewed preprint, now out in eLife!
With @spk3lly.bsky.social, @redmondoconnell.bsky.social and Anna Geuzebroek

elifesciences.org/reviewed-pre...

While we work on improving the [solid] paper based on the reviews, here are the key take-home messages:

Common neural choice signals reflect accumulated evidence, not confidence! Now out in @cerebralcortex.bsky.social w @helenevanmarcke.bsky.social @pierreledenmat.bsky.social @yfvisser.bsky.social @denizerdil.bsky.social a.o.

Paper: desenderlab.com/wp-content/u... Thread ↓↓↓

Will you be at #ICON2025 in Porto?
Then drop at our symposium on "Decision Signal(s) In The Electro-encephalogram" (SY23, Thursday at 13.45) with @redmondoconnell.bsky.social @nunezanalyzed.bsky.social @tarrynbalsdon.bsky.social @hcp4715.bsky.social organized by Leendert van Maanen and Jelmer Borst

Excited to be in Porto for #ICON2025! I will be at poster session 2 tomorrow (Tuesday) afternoon (P2.20) talking about evidence accumulation and choice-encoding centroparietal signals in the human EEG. Come say hi!

📢Fully Funded PhD position in Barcelona!

I'm excited to announce that I’m opening a PhD position at @idibaps.bsky.social, Barcelona!
We'll investigate the role of bodily signals in autobiographical memory, using virtual reality, EEG and TMS, in healthy volunteers and patient populations.

Excellent piece.

We know how to improve writing ability: it's by doing more, not less of it.

"LLMs do not improve one’s writing ability much like taking a taxi does not improve one’s driving ability. Students should hone their writing, thinking, and other academic skills at every opportunity."

Two flagship papers from the International Brain Laboratory, now out in ‪@Nature.com‬:
🧠 Brain-wide map of neural activity during complex behaviour: doi.org/10.1038/s41586-025-09235-0
🧠 Brain-wide representations of prior information in mouse decision-making: doi.org/10.1038/s41586-025-09226-1 +

New paper from the lab indicates some surprising differences in visual cortical contributions to two popular VEP types.
In it, Kieran uses some of his brilliant tricks from last year's paper:

Check out our new multisensory decision study!
We tackle a decades-old Q: does faster detection of bimodal targets come from a race or co-activation between modalities? And also a vital, orthogonal Q: is it one decision process or two?
A1: co-activation
A2: two!
Read here: rdcu.be/eASYd

A timely reminder that not everything can be outsourced - writing is thinking
www.nature.com/articles/s44...

CONVERSATIONS ON CONSCIOUSNESS
How the CCN Community Can Contribute

#CCN2025 on Wednesday 13th (10am 🇪🇺)
Livestream link below

➡️ Exploring the possibility of Computational Consciousness Science

➡️ Discussing three Templeton World Charity Foundation Adversarial Collaborations

Delighted to share this paper, now published in @arvoinfo.bsky.social. With @spk3lly.bsky.social‬ and Anna Geuzebroek we explored differences in visual cortical responses for pattern pulses and pattern reversals. Here's the link:
jov.arvojournals.org/article.aspx...

1/3 Check out our new commentary bsky.app/profile/imag....

Neurally-informed modelling unravels a single evidence accumulation process for choices and subsequent confidence reports Subjective confidence in perceptual choices depends on computations occurring prior to and after choice commitment. However, the nature of these computations remains unclear. Current models disagree o...

Our newest preprint is out (doi.org/10.1101/2025.06.05.658071), with @lucvermeylen.bsky.social,Dasha Monakhovych, Cameron McCabe, Sarah-Louise Mannion, @kobedesender.bsky.social, @redmondoconnell.bsky.social, comparing post-decision confidence models against behaviour and neural decision signals...

We believe our results hint at a flexible neural architecture that can adapt to different decision contexts, and highlight how the CPP may play a key intermediary role in adaptive evidence accumulation. Stay tuned for upcoming related work, and thanks for reading!

The way that the CPP behaves in this task seems very different from its well-established characteristics in static contexts with continuous evidence (e.g. classic random dot motion tasks), where it reflects the absolute cumulative sum of evidence.

Further, we found that the centroparietal positivity (CPP) tracks effective evidence (i.e. it reflects how much a DV changes following a token, rather than just stimulus information), but it does not keep a sustained representation of the DV.

Adaptive circuit dynamics across human cortex during evidence accumulation in changing environments - Nature Neuroscience Optimal decision making in a changing world requires non-linear evidence accumulation. Murphy et al. report signatures of this adaptive computation in recurrent dynamics of human parietal and motor co...

We found that motor beta lateralisation kept track of an evolving decision variable (DV) in a sustained manner over trial time, consistent with previous MEG work:
www.nature.com/articles/s41...

Because the normative solution to this task does not prescribe perfect accumulation, we could dissociate objective evidence presented on the screen from effective evidence (i.e. the belief updates that each token triggered), and map these quantities onto neural signals.

We used an expanded judgement task where participants watched a slow sequence of discrete tokens (400 ms per token, up to 10 tokens) which favoured one of two possible choices. The task was volatile, which means that the choice supported by the tokens may change within a trial.

Dissociable encoding of evolving beliefs and momentary belief updates in distinct neural decision signals - Nature Communications People are capable of making near-optimal decisions in volatile, changing environments. Here, the authors show how two neural decision signals encode distinct aspects of the belief updating process un...

Very happy to share this paper, now published in
@natcomms.nature.com! nature.com/articles/s41...
With @spk3lly.bsky.social and @neuromurphy.bsky.social, we investigated the neural computations that allow us to make near-optimal decisions in changing environments. Here's a short summary:

Disentangling sources of variability in decision-making - Nature Reviews Neuroscience Identifying the psychological and neurobiological processes underpinning intra-individual variations in choice behaviour presents a formidable challenge. In this Review, Duffy et al. discuss how algor...

In life, 3 things are certain: death, taxes, and decision-making variability🧠. Our review tinyurl.com/4dcwafc4 explores how computational models 💻 explain variability, their limits, and recent advances. A thread🧵👇

@redmondoconnell.bsky.social @neuromurphy.bsky.social Mark Bellgrove (not on Bluesky)

Individual variability of neural computations underlying flexible decisions - Nature Behavioural experiments to study decision-making in response to context-dependent accumulation of evidence provide testable models that are consistent with the heterogeneity in neural signatures among...

1/7 Our paper on individual variability in decision-making is finally out in @nature.com! Inspired by the classic work by Mante and Sussillo, we trained many rats to solve context-dependent decision-making, and we found that different brains use different neural mechanisms to solve the same task!