The human brain is intrinsically organized into dynamic, anticorrelated functional networks

TLDR

During attention‑demanding tasks, some brain regions consistently increase activity while others consistently decrease. The study investigates whether this task‑related activity dichotomy is reflected intrinsically in resting‑state fMRI fluctuations. They identified two widespread, diametrically opposed networks—one comprising regions that activate during tasks and the other comprising regions that deactivate—whose spontaneous correlations and anticorrelations reveal an intrinsic brain organization that underlies task‑driven responses.

Abstract

During performance of attention-demanding cognitive tasks, certain regions of the brain routinely increase activity, whereas others routinely decrease activity. In this study, we investigate the extent to which this task-related dichotomy is represented intrinsically in the resting human brain through examination of spontaneous fluctuations in the functional MRI blood oxygen level-dependent signal. We identify two diametrically opposed, widely distributed brain networks on the basis of both spontaneous correlations within each network and anticorrelations between networks. One network consists of regions routinely exhibiting task-related activations and the other of regions routinely exhibiting task-related deactivations. This intrinsic organization, featuring the presence of anticorrelated networks in the absence of overt task performance, provides a critical context in which to understand brain function. We suggest that both task-driven neuronal responses and behavior are reflections of this dynamic, ongoing, functional organization of the brain.