Spurious reconstruction from brain activity

Fuente: arXiv
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Autori principali: Shirakawa, Ken, Nagano, Yoshihiro, Tanaka, Misato, Aoki, Shuntaro C., Majima, Kei, Muraki, Yusuke, Kamitani, Yukiyasu
Natura: Preprint
Pubblicazione: 2024
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author Shirakawa, Ken
Nagano, Yoshihiro
Tanaka, Misato
Aoki, Shuntaro C.
Majima, Kei
Muraki, Yusuke
Kamitani, Yukiyasu
author_facet Shirakawa, Ken
Nagano, Yoshihiro
Tanaka, Misato
Aoki, Shuntaro C.
Majima, Kei
Muraki, Yusuke
Kamitani, Yukiyasu
contents Advances in brain decoding, particularly visual image reconstruction, have sparked discussions about the societal implications and ethical considerations of neurotechnology. As these methods aim to recover visual experiences from brain activity and achieve prediction beyond training samples (zero-shot prediction), it is crucial to assess their capabilities and limitations to inform public expectations and regulations. Our case study of recent text-guided reconstruction methods, which leverage a large-scale dataset (Natural Scene Dataset, NSD) and text-to-image diffusion models, reveals limitations in their generalizability. We found poor performance when applying these methods to a different dataset designed to prevent category overlaps between training and test sets. UMAP visualization of the text features with NSD images showed a limited diversity of semantic and visual clusters, with overlap between training and test sets. Formal analysis and simulations demonstrated that clustered training samples can lead to "output dimension collapse," restricting predictable output feature dimensions. Simulations further showed that diversifying the training set improved generalizability. However, text features alone are insufficient for mapping to the visual space. We argue that recent realistic reconstructions may primarily be a blend of classification into trained categories and generation of inauthentic images through text-to-image diffusion (hallucination). Diverse datasets and compositional representations spanning the image space are essential for genuine zero-shot prediction. Interdisciplinary discussions grounded in understanding the current capabilities and limitations, as well as ethical considerations, of the technology are crucial for its responsible development.
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id arxiv_https___arxiv_org_abs_2405_10078
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Spurious reconstruction from brain activity
Shirakawa, Ken
Nagano, Yoshihiro
Tanaka, Misato
Aoki, Shuntaro C.
Majima, Kei
Muraki, Yusuke
Kamitani, Yukiyasu
Neurons and Cognition
Advances in brain decoding, particularly visual image reconstruction, have sparked discussions about the societal implications and ethical considerations of neurotechnology. As these methods aim to recover visual experiences from brain activity and achieve prediction beyond training samples (zero-shot prediction), it is crucial to assess their capabilities and limitations to inform public expectations and regulations. Our case study of recent text-guided reconstruction methods, which leverage a large-scale dataset (Natural Scene Dataset, NSD) and text-to-image diffusion models, reveals limitations in their generalizability. We found poor performance when applying these methods to a different dataset designed to prevent category overlaps between training and test sets. UMAP visualization of the text features with NSD images showed a limited diversity of semantic and visual clusters, with overlap between training and test sets. Formal analysis and simulations demonstrated that clustered training samples can lead to "output dimension collapse," restricting predictable output feature dimensions. Simulations further showed that diversifying the training set improved generalizability. However, text features alone are insufficient for mapping to the visual space. We argue that recent realistic reconstructions may primarily be a blend of classification into trained categories and generation of inauthentic images through text-to-image diffusion (hallucination). Diverse datasets and compositional representations spanning the image space are essential for genuine zero-shot prediction. Interdisciplinary discussions grounded in understanding the current capabilities and limitations, as well as ethical considerations, of the technology are crucial for its responsible development.
title Spurious reconstruction from brain activity
topic Neurons and Cognition
url https://arxiv.org/abs/2405.10078