Is whole-brain functional connectivity a neuromarker of sustained attention? Comment on Rosenberg & al. (2016)

Abstract

Identification of neuromarkers accurately predicting cognitive characteristics from a single, standardised MRI scan could be tremendously useful in basic psychology and clinical practise. In a recent article, Rosenberg et al. (Nat Neurosci, 19, 165-171, 2016) argue that whole-brain functional network strength is a broadly applicable neuromarker of sustained attention. They claim that this marker accurately predicts performance from task related as well as resting state activity. Here, we discuss the applicability and generalizability in the context of three methodological concerns: Simulations show that the statistical methods for the 1) initial validation analyses as well as 2) internal validation using leave-one-out cross validation, are biased towards significance; 3) simple and complex models are compared suboptimally. Overall, we find that the article of Rosenberg et al. provides sufficient proof that network strength is associated with attentional capacity that it is not possible to say to which extent, and for this reason we argue that it cannot be concluded that the network is a broadly applicable neuromarker.