Predicting Brain Responses To Natural Movies With Multimodal LLMs

Fuente: arXiv
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Autori principali: Villanueva, Cesar Kadir Torrico, Tu, Jiaxin Cindy, Tripathy, Mihir, Lane, Connor, Iyer, Rishab, Scotti, Paul S.
Natura: Preprint
Pubblicazione: 2025
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author Villanueva, Cesar Kadir Torrico
Tu, Jiaxin Cindy
Tripathy, Mihir
Lane, Connor
Iyer, Rishab
Scotti, Paul S.
author_facet Villanueva, Cesar Kadir Torrico
Tu, Jiaxin Cindy
Tripathy, Mihir
Lane, Connor
Iyer, Rishab
Scotti, Paul S.
contents We present MedARC's team solution to the Algonauts 2025 challenge. Our pipeline leveraged rich multimodal representations from various state-of-the-art pretrained models across video (V-JEPA2), speech (Whisper), text (Llama 3.2), vision-text (InternVL3), and vision-text-audio (Qwen2.5-Omni). These features extracted from the models were linearly projected to a latent space, temporally aligned to the fMRI time series, and finally mapped to cortical parcels through a lightweight encoder comprising a shared group head plus subject-specific residual heads. We trained hundreds of model variants across hyperparameter settings, validated them on held-out movies and assembled ensembles targeted to each parcel in each subject. Our final submission achieved a mean Pearson's correlation of 0.2085 on the test split of withheld out-of-distribution movies, placing our team in fourth place for the competition. We further discuss a last-minute optimization that would have raised us to second place. Our results highlight how combining features from models trained in different modalities, using a simple architecture consisting of shared-subject and single-subject components, and conducting comprehensive model selection and ensembling improves generalization of encoding models to novel movie stimuli. All code is available on GitHub.
format Preprint
id arxiv_https___arxiv_org_abs_2507_19956
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Predicting Brain Responses To Natural Movies With Multimodal LLMs
Villanueva, Cesar Kadir Torrico
Tu, Jiaxin Cindy
Tripathy, Mihir
Lane, Connor
Iyer, Rishab
Scotti, Paul S.
Computer Vision and Pattern Recognition
Artificial Intelligence
Neurons and Cognition
We present MedARC's team solution to the Algonauts 2025 challenge. Our pipeline leveraged rich multimodal representations from various state-of-the-art pretrained models across video (V-JEPA2), speech (Whisper), text (Llama 3.2), vision-text (InternVL3), and vision-text-audio (Qwen2.5-Omni). These features extracted from the models were linearly projected to a latent space, temporally aligned to the fMRI time series, and finally mapped to cortical parcels through a lightweight encoder comprising a shared group head plus subject-specific residual heads. We trained hundreds of model variants across hyperparameter settings, validated them on held-out movies and assembled ensembles targeted to each parcel in each subject. Our final submission achieved a mean Pearson's correlation of 0.2085 on the test split of withheld out-of-distribution movies, placing our team in fourth place for the competition. We further discuss a last-minute optimization that would have raised us to second place. Our results highlight how combining features from models trained in different modalities, using a simple architecture consisting of shared-subject and single-subject components, and conducting comprehensive model selection and ensembling improves generalization of encoding models to novel movie stimuli. All code is available on GitHub.
title Predicting Brain Responses To Natural Movies With Multimodal LLMs
topic Computer Vision and Pattern Recognition
Artificial Intelligence
Neurons and Cognition
url https://arxiv.org/abs/2507.19956