Seeing the imagined: a latent functional alignment in visual imagery decoding from fMRI data

Fuente: arXiv
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Auteurs principaux: Spera, Fabrizio, Boccato, Tommaso, Olak, Michal, Cammarota, Sara, Ciferri, Matteo, Tronti, Michelangelo, Toschi, Nicola, Ferrante, Matteo
Format: Preprint
Publié: 2026
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author Spera, Fabrizio
Boccato, Tommaso
Olak, Michal
Cammarota, Sara
Ciferri, Matteo
Tronti, Michelangelo
Toschi, Nicola
Ferrante, Matteo
author_facet Spera, Fabrizio
Boccato, Tommaso
Olak, Michal
Cammarota, Sara
Ciferri, Matteo
Tronti, Michelangelo
Toschi, Nicola
Ferrante, Matteo
contents Recent progress in visual brain decoding from fMRI has been enabled by large-scale datasets such as the Natural Scenes Dataset (NSD) and powerful diffusion-based generative models. While current pipelines are primarily optimized for perception, their performance under mental-imagery remains less well understood. In this work, we study how a state-of-the-art (SOTA) perception decoder (DynaDiff) can be adapted to reconstruct imagined content from the Imagery-NSD benchmark. We propose a latent functional alignment approach that maps imagery-evoked activity into the pretrained model's conditioning space, while keeping the remaining components frozen. To mitigate the limited amount of matched imagery-perception supervision, we further introduce a retrieval-based augmentation strategy that selects semantically related NSD perception trials. Across four subjects, latent functional alignment consistently improves high-level semantic reconstruction metrics relative to the frozen pretrained baseline and a voxel-space ridge alignment baseline, and enables above-chance decoding from multiple cortical regions. These results suggest that semantic structure learned from perception can be leveraged to stabilize and improve visual imagery decoding under out-of-distribution conditions.
format Preprint
id arxiv_https___arxiv_org_abs_2604_15374
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Seeing the imagined: a latent functional alignment in visual imagery decoding from fMRI data
Spera, Fabrizio
Boccato, Tommaso
Olak, Michal
Cammarota, Sara
Ciferri, Matteo
Tronti, Michelangelo
Toschi, Nicola
Ferrante, Matteo
Neurons and Cognition
Artificial Intelligence
Image and Video Processing
Recent progress in visual brain decoding from fMRI has been enabled by large-scale datasets such as the Natural Scenes Dataset (NSD) and powerful diffusion-based generative models. While current pipelines are primarily optimized for perception, their performance under mental-imagery remains less well understood. In this work, we study how a state-of-the-art (SOTA) perception decoder (DynaDiff) can be adapted to reconstruct imagined content from the Imagery-NSD benchmark. We propose a latent functional alignment approach that maps imagery-evoked activity into the pretrained model's conditioning space, while keeping the remaining components frozen. To mitigate the limited amount of matched imagery-perception supervision, we further introduce a retrieval-based augmentation strategy that selects semantically related NSD perception trials. Across four subjects, latent functional alignment consistently improves high-level semantic reconstruction metrics relative to the frozen pretrained baseline and a voxel-space ridge alignment baseline, and enables above-chance decoding from multiple cortical regions. These results suggest that semantic structure learned from perception can be leveraged to stabilize and improve visual imagery decoding under out-of-distribution conditions.
title Seeing the imagined: a latent functional alignment in visual imagery decoding from fMRI data
topic Neurons and Cognition
Artificial Intelligence
Image and Video Processing
url https://arxiv.org/abs/2604.15374