fMRI Semantic Category Decoding using Linguistic Encoding of Word Embeddings

TL;DR

This paper introduces a novel linguistic encoding-based model for decoding semantic categories from fMRI data, demonstrating superior performance with Meta-Embeddings compared to other word feature models.

Contribution

The study presents a new approach using linguistic encodings like Meta-Embeddings for semantic decoding of fMRI data, outperforming previous models with hand-crafted features.

Findings

Meta-Embeddings achieve state-of-the-art fMRI decoding performance.

Models with GloVe and Word2Vec features perform similarly to existing models.

The proposed approach is simple, effective, and improves semantic decoding accuracy.

Abstract

The dispute of how the human brain represents conceptual knowledge has been argued in many scientific fields. Brain imaging studies have shown that the spatial patterns of neural activation in the brain are correlated with thinking about different semantic categories of words (for example, tools, animals, and buildings) or when viewing the related pictures. In this paper, we present a computational model that learns to predict the neural activation captured in functional magnetic resonance imaging (fMRI) data of test words. Unlike the models with hand-crafted features that have been used in the literature, in this paper we propose a novel approach wherein decoding models are built with features extracted from popular linguistic encodings of Word2Vec, GloVe, Meta-Embeddings in conjunction with the empirical fMRI data associated with viewing several dozen concrete nouns. We compared these models with several other models that use word features extracted from FastText, Randomly-generated features, Mitchell's 25 features [1]. The experimental results show that the predicted fMRI images using Meta-Embeddings meet the state-of-the-art performance. Although models with features from GloVe and Word2Vec predict fMRI images similar to the state-of-the-art model, model with features from Meta-Embeddings predicts significantly better. The proposed scheme that uses popular linguistic encoding offers a simple and easy approach for semantic decoding from fMRI experiments.