Non-invasive Neural Decoding in Source Reconstructed Brain Space
Yonatan Gideoni, Ryan Charles Timms, Oiwi Parker Jones

TL;DR
This paper introduces a method for non-invasive neural decoding that reconstructs brain activity in source space, enabling improved generalization, interpretability, and data harmonization across different neuroimaging datasets.
Contribution
It demonstrates that source reconstruction allows MEG data to be decoded in brain space, facilitating spatial biases and zero-shot generalization.
Findings
Enables spatial inductive biases in neural decoding.
Improves interpretability of MEG data.
Achieves zero-shot generalization across datasets.
Abstract
Non-invasive brainwave decoding is usually done using Magneto/Electroencephalography (MEG/EEG) sensor measurements as inputs. This makes combining datasets and building models with inductive biases difficult as most datasets use different scanners and the sensor arrays have a nonintuitive spatial structure. In contrast, fMRI scans are acquired directly in brain space, a voxel grid with a typical structured input representation. By using established techniques to reconstruct the sensors' sources' neural activity it is possible to decode from voxels for MEG data as well. We show that this enables spatial inductive biases, spatial data augmentations, better interpretability, zero-shot generalisation between datasets, and data harmonisation.
Peer Reviews
Decision·Submitted to ICLR 2025
The promising study introduces a large body of experimental effort on a relatively less explored field, MEG data. The code and pipelines in this work can contribute to increasing interest in the field. Source space reconstruction of MEG data is a solid goal, albeit a well-studied one. Enabled by the common source template, combining multi-subject datasets improves single subject performance.
1- The claims, that being the first study to apply CNN architecture or spatial augmentations in the MEG field might be too strong, as some other previous studies [1, 2] worked on very similar goals. 2- Better separating MEG field technicalities and machine learning related details can expand the audience of the work. The article might benefit from a more compact writing style to include figures and definition tables that can guide the reader. 3- As the MEG data is source reconstructed, source
- The study conducts comprehensive experiments demonstrating that converting surface brain signals into source space provides a more effective input representation, facilitating neural decoding.
- This study is primarily exploratory, focusing on the differences between various input forms. As a result, the technical contributions may appear limited to readers in the ICLR community. This paper might be better suited for publication in a more specialized journal within this field. - The organization of this paper is difficult to follow, which might due to the absence of subtitles (like for the Dataset/Method/Implement detail ...). Additionally, a clearer structure would enhance the overa
The experimental design is relevant to the question. Pipelines based on the source and sensor-space representations are carefully optimized for hyperparameters. A number of data augmentation strategies are detailed. There is an attempt at explainable AI.
1) The question of decoding source and sensor space for M/EEG is not novel, key works include Edelman et al. 2015. EEG source imaging enhances the decoding of complex right-hand motor imagery tasks. IEEE Transactions on Biomedical Engineering, 63(1), pp.4-14. (300+ citations) Andersen et al. 2017, March. EEG source imaging assists decoding in a face recognition task. In 2017 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP) pp. 939-943. Li et al. 2021. A novel de
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Taxonomy
TopicsNeural Networks and Applications · Fractal and DNA sequence analysis
