Brain Biomarker Interpretation in ASD Using Deep Learning and fMRI
This work addresses the need for interpretable biomarkers in ASD diagnosis, which could aid in earlier diagnosis and targeted treatment, but it is incremental as it builds on existing deep learning applications in fMRI.
The authors tackled the problem of interpreting biomarkers for autism spectrum disorder (ASD) using fMRI and deep learning, proposing a 2-stage method that classifies ASD vs. control subjects and interprets saliency features, with the biomarkers found being robust and consistent with previous literature.
Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder. Finding the biomarkers associated with ASD is extremely helpful to understand the underlying roots of the disorder and can lead to earlier diagnosis and more targeted treatment. Although Deep Neural Networks (DNNs) have been applied in functional magnetic resonance imaging (fMRI) to identify ASD, understanding the data-driven computational decision making procedure has not been previously explored. Therefore, in this work, we address the problem of interpreting reliable biomarkers associated with identifying ASD; specifically, we propose a 2-stage method that classifies ASD and control subjects using fMRI images and interprets the saliency features activated by the classifier. First, we trained an accurate DNN classifier. Then, for detecting the biomarkers, different from the DNN visualization works in computer vision, we take advantage of the anatomical structure of brain fMRI and develop a frequency-normalized sampling method to corrupt images. Furthermore, in the ASD vs. control subjects classification scenario, we provide a new approach to detect and characterize important brain features into three categories. The biomarkers we found by the proposed method are robust and consistent with previous findings in the literature. We also validate the detected biomarkers by neurological function decoding and comparing with the DNN activation maps.