Dr. Cerejeira has been PI or Co-Investigator in several clinical studies with publication of scientific papers and presentation of results in international and national meetings. His research interests have been focused in the development of peripheral biomarkers of delirium and in particular investigating the cross-talk between the brain and the body through the blood-brain barrier. His PhD thesis consisted in determining the levels of several peripheral biomarkers in subjects undergoing elective surgery and relate biomarkers levels with the occurrence of delirium. Based on his work he suggested the “neuroinflammatory hypothesis” of delirium and during the last years he has been collaborating with researchers from a diversity of centers, including in Portugal, UK, Italy, Brazil and United States in studies exploring this hypothesis. More recently, he has been studying the homeostatic adaptations to acute medical illness and how this can trigger brain dysfunction particularly when affected by prior neurodegeneration