🤖 AI Summary
Existing brain-to-image reconstruction methods struggle to simultaneously preserve semantic content and fine-grained structural details—such as spatial position, orientation, and scale—resulting in limited controllability and interpretability. This work proposes MindDiffuser, a two-stage framework that first leverages CLIP text embeddings decoded from neural signals to guide Stable Diffusion in generating semantically coherent images, and then iteratively refines these outputs by aligning them with shallow CLIP visual features also decoded from brain activity. By integrating semantic guidance with structural alignment for the first time, MindDiffuser achieves high-fidelity, controllable image reconstruction across multiple neuroimaging modalities—including fMRI, EEG, and MEG—significantly outperforming existing approaches in both semantic accuracy and structural consistency, while also enhancing the model’s neurobiological plausibility.
📝 Abstract
Reconstructing visual stimuli from brain recordings has been a meaningful and challenging task in brain decoding. Especially, the achievement of precise and controllable image reconstruction bears great significance in propelling the progress and utilization of brain-computer interfaces. Recent methods, leveraging advances in the power of text-to-image generation models, have reconstructed images that closely approximate complex natural stimuli in terms of semantics (e.g., concepts and objects). However, they struggle to maintain consistency with the original stimuli in fine-grained structural information (e.g., position, orientation and size), which undermines both the controllability and interpretability of the models. To address the aforementioned issues, we propose a two-stage image reconstruction framework, termed MindDiffuser. In Stage 1, Contrastive Language-Image Pretraining (CLIP) text embeddings decoded from brain responses are input into Stable Diffusion, generating a preliminary image containing semantic information. In Stage 2, we use decoded shallow CLIP visual features as supervisory signals, iteratively refining the feature vectors from Stage 1 via backpropagation to align structural information. We conducted extensive experiments on brain response datasets across three modalities (fMRI, EEG, MEG) elicited by visual stimuli, demonstrating that our framework significantly enhances the performance of previous state-of-the-art models, highlighting the effectiveness and versatility of our approach. Spatial and temporal visualization results further support the neurobiological plausibility of our framework, providing guidance for future neural decoding efforts across different brain signal modalities.