Male and Female Brain Coherence Models of Cognitive Performance and Psychopathology

Finding reliable imaging biomarkers of mental illness has been a major challenge, on a par with the quest for biomarkers of the male versus the female brain, as the two types of imaging inform one another. We explored the hypothesis that the degree of coherence (internal isomorphism) between brain volumes of the left versus the right hemisphere for patients with psychopathological conditions follows the brain coherence pattern of the healthy male or healthy female. We developed the ‘distance index’ (DI) as a biomarker of brain coherence and compared it with three ad hoc coherence measures. We found that only DI could reliably distinguish males from females and patients from controls. Also, cortical regions with highest DI scores were swapped between males and females across groups following male/female models of psychopathology. Furthermore, although indices were similar in predicting cognitive performance, DI provided a more proportionate prediction pattern across diagnosis groups, and more robust interactions with males/females. These findings highlight the importance of brain coherence, particularly measured by DI, for phenotyping sex and mental illness.