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Olivia Christiano

@oliviachristiano.bsky.social

41 followers 75 following 8 posts

PhD student @yale.edu Interested in the neural basis of attention & memory 🧠

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Reposted by Olivia Christiano

Sebastian Michelmann @s-michelmann.bsky.social · Sep 5

🚀Excited to share our project: Canonical Representational Mapping for Cognitive Neuroscience. @schottdorflab.bsky.social and I propose a novel multivariate method to isolate neural representations aligned with specific cognitive hypotheses 🧵https://www.biorxiv.org/content/10.1101/2025.09.01.673485v1

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Olivia Christiano @oliviachristiano.bsky.social · Jul 19

Huge thanks to the many people who made this project possible by generously making their data available! @urihasson.bsky.social‬‬ ‪@chrishoney.bsky.social‬ @sparsity.bsky.social ‪@lukas-rier.bsky.social‬ Matt Brookes and Elena Boto!

Olivia Christiano @oliviachristiano.bsky.social · Jul 19

These findings highlight OPM-MEG’s potential as a flexible, noninvasive tool capable of capturing complex neural activity with high reliability. 🧠✅

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Olivia Christiano @oliviachristiano.bsky.social · Jul 19

Finally, we compared z-scores across conditions. Permutation testing identified areas with significant reliability differences.

4. Surprisingly–in some regions–SNR estimates between OPM & fMRI (red) exceeded OPM alone. In others OPM alone exceeded the OPM & fMRI comparison (green).

📊 Fig 7

Between-modality SNR differences contrast the SNR from between-subject OPM comparisons with the SNR from between-method OPM-to-fMRI comparisons. Negative values (green) indicate greater signal reliability within the OPM sample than in the cross-modal comparison. Positive values (red) indicate greater signal reliability in the cross-modal comparison (fMRI-to-OPM) than within the OPM sample. Significant clusters surviving multiple comparison correction (FDR q < .025) are outlined in the respective color. SNR changes are shown for the high-frequency (64-116 Hz) band.

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Olivia Christiano @oliviachristiano.bsky.social · Jul 19

3. OPM signals correlated more strongly with fMRI than iEEG, especially in visual areas. OPM to fMRI correlations followed the expected inverse relationship with BOLD signals: negative correlations at low frequencies, positive correlations at higher frequencies.

📊 Fig 5

Z-scores from cross-modal correlations between OPM subjects (n = 10) and fMRI subjects (n = 11) are shown for 3581 locations in the θ, α, β, and HF bands.

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Olivia Christiano @oliviachristiano.bsky.social · Jul 19

2. Between-subject correlation maps were more spatially focused in sensory regions

📊 Fig 4

Z-scores surviving correction for multiple comparison of between-subject correlations are shown for: (A) OPM, 3581 source locations across 10 subjects in the θ, α, and β bands; (B) fMRI, 3581 voxels across 11 subjects.

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Olivia Christiano @oliviachristiano.bsky.social · Jul 19

1. OPMs showed high test-retest reliability, especially at lower frequencies, often on par with reliability in fMRI and iEEG.

Z-scores reflect signal correlation relative to correlations of phase-shuffled data.

📊 Fig 3

Z-scores surviving correction for multiple comparison of within-subject correlations are shown for: (A) OPM, 3581 source locations across 10 subjects in the δ (0.5–4 Hz), θ (4–8 Hz), α (8–12 Hz) and β (12–28 Hz) bands; (B) fMRI, 3581 voxels across 11 subjects; (C) iEEG, 656 electrodes pooled across five subjects in the δ, θ, and α bands.

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Olivia Christiano @oliviachristiano.bsky.social · Jul 19

Three separate groups watched a short movie twice while neural activity was recorded via OPMs, fMRI, or iEEG.

We quantified:
1. Within-subject reliability
2. Shared signal across subjects (ISC)
3. Shared signal across methods
4. SNR within & across OPM subjects, and between OPM & fMRI

📊 Fig 1

Within-subject correlations (blue) were computed between the first and second viewing for each subject and averaged across the respective group; for iEEG, electrodes were treated as a single subject. Between-subject correlations (green) were computed across viewings, averaging correlations from viewing 1 to viewing 2 (solid) and vice versa (dashed), comparing each subject to the rest of their group. Between-method correlations (red) were computed similarly, comparing each subject i in one modality to each subject j in another, or to the single-subject iEEG dataset.

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Olivia Christiano @oliviachristiano.bsky.social · Jul 19

How reliable is OPM-MEG, and how does it compare to other neuroimaging modalities? 🤔

In a new preprint with ‪@s-michelmann.bsky.social‬, we evaluate the reliability of OPM-MEG within & between individuals, and compare it to fMRI & iEEG during repeated movie viewing. 🧠

📄 doi.org/10.1101/2025...

Reliability and signal comparison of OPM-MEG, fMRI & iEEG in a repeated movie viewing paradigm

Optically pumped magnetometers (OPMs) offer a promising advancement in noninvasive neuroimaging via magnetoencephalography (MEG), but establishing their reliability and comparability to existing metho...

doi.org

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