Resting-state functional connectivity correlates with spontaneous causal interactions

In this study, we explored the neural basis of resting-state FC in mice by employing fMRI combined with optogenetic silencing, which suppresses excitatory neuron activity to enable the measurement of spontaneous causal interactions. Spontaneous connectivity patterns resemble the bilateral patterns of resting-state FC, contrasting with the predominantly ipsilateral connectivity observed during optogenetic activation. Additionally, spontaneous activity was found to propagate through polysynaptic structural pathways, whereas evoked activity was primarily restricted to monosynaptic pathways. This finding suggests that FC emerges from causal interactions driven by ongoing spontaneous neural activity.