摘要Functional magnetic resonance imaging(fMRI)is a popular tool used to investigate not only how the brain responds to specific stimuli during sensorimotor or cognitive tasks,but also brain activity at rest.The physics beyond this approach is based on the analysis of the blood oxygenation level-dependent signal.When performing a task,regions activated by a specific goal exhibit changes in the blood oxygenation level-dependent signal compared to the resting phase.Looking at the difference between the task-evoked signal and the spontaneous fluctuations allows identifying which brain regions are activated by specific tasks.However,spontaneous fluctuations are no more considered as a mere epiphenomenon as they allow unravelling how the brain"works"during resting state conditions.This approach is referred to as resting-state fMRI(rs-fMRI).Starting from this signal it is possible to quantify the functional connectivity(FC),a metric used to identify which brain regions show signal synchronization,and therefore are considered functionally connected within specific resting-state networks.Each resting-state network is characterized by specific spatiotemporal patterns,linked with sensory and high-cognitive order functions(e.g.,memory,attention,and language),as highlighted by a study by Yeo et al.(2011).Being vascular in nature,rs-fMRI represents an indirect measure of neural connectivity.Despite this limitation,the study of rs-fMRI signals deeply increased our knowledge about brain mechanisms underlying cognitive and sensory abilities.