Dominika Varga
@dkvarga.bsky.social
410 followers 220 following 11 posts
Postdoctoral Researcher in the Vaghi Lab - Birkbeck Studying how individual brain circuits support learning and goal directed behaviour Previously at Sussex Episodic Memory Group
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dkvarga.bsky.social
Thank you Matilde for the warm welcome, very excited to be part of the team! 🤩
Reposted by Dominika Varga
matildevaghi.bsky.social
🚨 PhD opportunity (start Oct 2026) with @birkbeckpsychology.bsky.social via UBEL DTP !

I’m looking for students keen to study cognitive & brain mechanisms of compulsivity through computational modelling 📊, advanced neuroimaging 🧠 & normative models 📈

Get in touch if this excites you!
dkvarga.bsky.social
Very grateful to our team for their collaboration on this project: @praykov.bsky.social , @ayab.bsky.social , @chrismbird.bsky.social , Beth Jefferies
dkvarga.bsky.social
Please check out the paper for more findings on how mismatches impact memory and activity in cortical networks and subcortical regions-of-interest. To check out our pre-registrations and materials, please visit here: osf.io/p6z2g/
See an example video clip here: e01.eventmemory.org/ExampleVid_p...
dkvarga.bsky.social
These findings provide support to models of hippocampal function that identify a limited role in comparing incoming info with memories stored within the hippocampus. Conversely, models that propose a more general role in comparing broader contextual representations to reality should be re-evaluated.
dkvarga.bsky.social
Overall, regardless of general context-typicality, the hippocampus responded to events that mismatched specific episodic memories.
dkvarga.bsky.social
When people formed episodic memories of the Typical actions prior to scanning, the Atypical actions now increased hippocampal response (Exp2). When people prewatched the Atypical version of the clips, now the contextually appropriate Typical actions increased hippocampal response (Exp3).
dkvarga.bsky.social
In Exp1, when people hadn't seen any clips pre-scanning, hippocampal activity was not modulated by the expectedness of actions based on schema knowledge alone. However, in Exp2 and 3, when actions mismatched memories of the clips seen pre-scanning, hippocampal activity increased. (cont.)
Hippocampal mismatch response is limited to signaling episodic memory–based mismatches. In Experiment 1, expectations are based only on schematic knowledge, in Experiment 2, expectations are based on both episodic memory and schematic knowledge, and in Experiment 3, expectations are based only on episodic memory. Bar charts showing the average response to Typical and Atypical target actions in the bilateral hippocampus in the three experiments (strip plots show individual participants’ averaged parameter estimates for the target actions estimated from a GLM). Error bars represent 95% CIs.
dkvarga.bsky.social
Inside an fMRI scanner, people viewed clips of everyday events (e.g., doing the laundry), which could be Typical (putting clothes) or Atypical (putting flowers). To test what prior expectations the hippocampus uses to detect mismatches, we manipulated clip familiarity pre-scanning across experiments
Experimental paradigm. (A) Still frames showing example moments from the two alternative versions of the “laundry” video clip (watch the clips here: https://e01.eventmemory.org/ExampleVid_paper.html). The two versions showed a nearly identical sequence of actions, except for the target action that was either Typical or Atypical. (B) Before scanning, participants either did not watch any clips (Experiment 1), watched the Typical version of each clip (Experiment 2), or watched the Atypical version of each clip (Experiment 3). Across three experiments, all participants watched half of the clips in the Typical and the other in the Atypical version during fMRI. By manipulating prescan familiarity with the clips, target actions in each experiment violated different types of expectations. After scanning, participants were asked to describe what happened in all video clips watched inside the scanner, focusing on the actions the actors performed, cued by the first frame of each clip.
dkvarga.bsky.social
The hippocampus is thought to detect mismatches by comparing expectations with reality. However, it was unclear whether it serves as a general mismatch detector, flagging any event that violates our general model of the world, or whether it monitors reality against specific episodic memories.
dkvarga.bsky.social
In daily life, we rely on our internal models of the world to predict what happens next—e.g., anticipating someone’s actions while they do laundry. 👇
But sometimes our prior expectations don’t match reality. These mismatches are important for updating our models and learning. How do we detect them?
dkvarga.bsky.social
So happy to share our paper on the role of the hippocampus as a mismatch detector:
doi.org/10.1073/pnas...

We show that the hippocampus detects mismatches between ongoing experiences and episodic memories but not generalised schematic knowledge.

See 🧵for how we got here:
#neuroskyence #PsychSciSky