Causal evidence of coherent theta rhythms in the modulation of multiregional brain communication

Neuromodulatory interventions seek to treat neuropsychiatric disorders by manipulating multiregional communication across the mesolimbic mood network. Modulations of multiregional communication are rarely measured directly and are often inferred from correlated neural activity such as neural coherence. Whether and how neural coherence reflects dynamic multiregional communication remains unclear. To address this limitation, we performed a causal-correlation analysis of theta-frequency (4-10 Hz) rhythms and mesolimbic multiregional communication. Selectively stimulating sender sites while recording from receiver sites revealed a mechanism of dynamic multiregional communication involving theta-coherent neural dynamics across a network of sender-receiver-modulator sites. Modulator site activity was highly theta-coherent with the receiver site activity, less theta-coherent with sender site activity, site specific and not shared by neighboring sites in the same region. These results reveal fundamental mechanisms of dynamic multiregional communication and support the use of theta-coherence as a target for neuromodulatory interventions in the mesolimbic mood network.