Biomarkers indicate a biological state and here, several findings on event-related potentials are summarised (potentials and connectivity in schizophrenia, ADHD, obsessive-compulsive disorder, etc.). Evoked components and oscillatory changes map to cognitive constructs, and therefore task induced oscillatory changes could be a new frontier in objective markers for cognitive disorders. With simple tasks, if well-specified for our hypotheses, we may benefit from M/EEG temporal resolution for this aim.