Hierarchical Gating of Cortical Population Dynamics Drives Pain
The prefrontal cortex and anterior cingulate cortex are key cortical hubs for pain regulation, yet the functional hierarchy between them remains unclear. We examined how the prelimbic cortex (PL) to ACC pathway regulates nociceptive processing and pain behavior in freely moving rats across synaptic, cellular, and network levels. Activation of the PL to ACC pathway reduced aversion to both evoked and spontaneous pain, whereas inhibition increased pain aversion, indicating that this circuit exerts tonic modulatory control. Meanwhile, ex vivo electrophysiology revealed that PL inputs recruit local ACC interneurons to produce feedforward inhibition of ACC pyramidal neurons. At the cellular level, in vivo microendoscopic calcium imaging showed that optogenetic activation of PL axon terminals suppresses nociceptive-evoked activity of ACC pyramidal neurons. At the network level, PL activation reduced pain-induced excitability while centralizing nociceptive information flow within the ACC, resulting in a gated, low output population state. Overall, these findings identify a hierarchically organized cortical circuit that tonically controls pain related sensory and affective experience.