Bradley S. Peterson, M.D.
SUMMARY: In his presentation, Dr. Bradley Peterson summarized and provided examples of the conceptual, methodological, and statistical challenges of using neuroimaging to understand developmentally based psychopathologies. He explained that an individual’s adaptation to debilitating symptoms will likely alter broadly distributed brain systems, thus making it difficult to distinguish adaptive changes from the pathological processes that induced the compensatory changes. The challenge, according to Peterson, is to distinguish findings that represent core pathophysiology from epiphenomena (arising as a result of the illness) and from findings arising from adaptive changes.
Similarly, delineating the natural history and developmental correlates of an illness is also challenging. Researchers often assume that cross-sectional studies belong to a larger general population of individuals with the same biological disease, presuming that younger subjects will eventually resemble older counterparts. Peterson cautioned that this assumption is often false, and that most childhood-onset illnesses differ from their adult counterparts in associated comorbidities, degree of familial risk, and other factors.
Peterson concluded by suggesting that ensuing imaging studies of developmentally based psychopathologies move from convenient sample groups in temporal cross-section to representative samples using novel and more informative experimental designs. He also recommended that (1) progressively younger age groups and high-risk cohorts be included in future studies; (2) imaging studies be linked with clinical trials so that the causally relevant variable under study can be experimentally controlled and manipulated; and (3) fMRI studies include basic elementary tasks that differ minimally across groups in performance and processing strategies to better define origins and timing of differences when they first appear.