Abnormal network topographies and changes in global activity: absence of a causal relationship.

ABSTRACT: Changes in regional brain activity can be observed following global normalization procedures to reduce variability in the data. In particular, spurious regional differences may appear when scans from patients with low global activity are compared to those from healthy subjects. It has thus been suggested that the consistent increases in subcortical activity that characterize the abnormal Parkinson's disease-related metabolic covariance pattern (PDRP) are artifacts of global normalization, and that similar topographies can be identified in scans from healthy subjects with varying global activity. To address this issue, we examined the effects of experimental reductions in global metabolic activity on PDRP expression. Ten healthy subjects underwent ¹⁸F-fluorodeoxyglucose PET in wakefulness a

SUBMITTER: Dhawan V 

PROVIDER: S-EPMC3474325 | biostudies-literature | 2012 Dec

REPOSITORIES: biostudies-literature