1. A method of estimating the likelihood of brain concussion from neurophysiological data acquired from the brain of the subject, comprising: using a data processor for: identifying activity-related features in said data; constructing a subject-specific brain network activity (BNA) pattern having a plurality of nodes, wherein each node represents a feature of said activity-related features, and each pair of nodes is assigned with a connectivity weight; calculating a BNA pattern similarity describing a comparison between said constructed BNA pattern and a baseline BNA pattern being specific to the subject; and assessing the likelihood of brain concussion responsively to said BNA pattern similarity.