Brain Decodes Deep Nets

Abstract

We developed a tool for visualizing and analyzing large pre-trained vision models by mapping them onto the brain thus exposing their hidden inside. Our innovation arises from a surprising usage of brain encoding: predicting brain fMRI measurements in response to images. We report two findings. First explicit mapping between the brain and deep-network features across dimensions of space layers scales and channels is crucial. This mapping method FactorTopy is plug-and-play for any deep-network; with it one can paint a picture of the network onto the brain (literally!). Second our visualization shows how different training methods matter: they lead to remarkable differences in hierarchical organization and scaling behavior growing with more data or network capacity. It also provides insight into fine-tuning: how pre-trained models change when adapting to small datasets. We found brain-like hierarchically organized network suffer less from catastrophic forgetting after fine-tuned.