Even mild cases of COVID-19 are associated with brain changes including decreased grey matter, an overall reduction in brain volume, and cognitive decline, a new imaging study shows. In this first study to use magnetic resonance brain imaging, before and after COVID-19, investigators — Dr Gwenaëlle Douaud and team at Wellcome Center for Integrative Neuroimaging, Nuffield Department of Clinical Neurosciences, University of Oxford, found “greater reduction in grey matter thickness and tissue-contrast in the orbitofrontal cortex and parahippocampal gyrus, greater changes in markers of tissue damage in regions functionally connected to the primary olfactory cortex and greater reduction in global brain size.” However, the researchers urge caution when interpreting the findings.