Figure 1. .

Functional anticorrelations might emerge as a result of local and long-range inhibitory activity. Brain regions are modeled by interconnected populations of excitatory (E) and inhibitory (I) neurons. Long-range excitatory connections from brain region A to brain region B can target the excitatory population (E → E, solid blue) or the inhibitory population (E → I, dashed blue). The level of inhibition in region B depends i) on the local E-I loop (local feedback inhibition) and ii) on the excitatory inputs from region A to the inhibitory neurons in region B, which in turn connect locally to the excitatory cells (long-range feedforward inhibition, gray highlighted path). With this model, we postulate that neural inhibition assists the emergence of the anticorrelations not by direct internetwork, interareal inhibition (of note, most interareal connections around the brain are glutamatergic). Rather, anticorrelations appear indirectly after disrupting both local and global balance between excitation and inhibition, eventually affecting network metastability.