Mind Reader: Reconstructing complex images from brain activities

TL;DR

This paper presents a novel method for reconstructing complex, semantically rich images from fMRI brain signals by leveraging a multi-modal approach with text and a pre-trained vision-language latent space, achieving realistic and accurate image reconstructions.

Contribution

It introduces a multi-modal reconstruction framework that incorporates text and a pre-trained latent space to improve image reconstruction from brain activity data.

Findings

Reconstructed images are photo-realistic and semantically accurate.

Inclusion of text modality enhances reconstruction quality.

Leveraging pre-trained latent space addresses data scarcity effectively.

Abstract

Understanding how the brain encodes external stimuli and how these stimuli can be decoded from the measured brain activities are long-standing and challenging questions in neuroscience. In this paper, we focus on reconstructing the complex image stimuli from fMRI (functional magnetic resonance imaging) signals. Unlike previous works that reconstruct images with single objects or simple shapes, our work aims to reconstruct image stimuli that are rich in semantics, closer to everyday scenes, and can reveal more perspectives. However, data scarcity of fMRI datasets is the main obstacle to applying state-of-the-art deep learning models to this problem. We find that incorporating an additional text modality is beneficial for the reconstruction problem compared to directly translating brain signals to images. Therefore, the modalities involved in our method are: (i) voxel-level fMRI signals, (ii) observed images that trigger the brain signals, and (iii) textual description of the images. To further address data scarcity, we leverage an aligned vision-language latent space pre-trained on massive datasets. Instead of training models from scratch to find a latent space shared by the three modalities, we encode fMRI signals into this pre-aligned latent space. Then, conditioned on embeddings in this space, we reconstruct images with a generative model. The reconstructed images from our pipeline balance both naturalness and fidelity: they are photo-realistic and capture the ground truth image contents well.