Dopamine synchronizes hippocampal-prefrontal networks

Abstract

Interactions among brain networks support cognition and behavior. Oscillatory activity may contribute to this process by coordinating distant neuronal populations. A crucial step toward elucidating brain function and its emergent properties is understanding the mechanisms that dynamically modulate functional connectivity in response to environmental challenges and physiological demands. Dopamine (DA) is well-positioned to modulate this process, given its role in altering neuronal excitability and regulating oscillatory cognitive networks, such as the hippocampus-prefrontal cortex (HPC-PFC) networks. However, it is mostly unknown how dopamine modulates HPC-PFC synchrony. Here, we recorded HPC and PFC activity in rats while manipulating dopamine levels. Our results show that dopamine dose-dependently induces HPC-PFC theta synchrony. This effect was not reproduced by selective activation of D1-like (SKF-38393) or D2-like (quinpirole) receptors, nor by the D1/D2 non-selective agonist apomorphine. Thus, dopamines modulatory effects on HPC-PFC activity may depend on the precise interplay between dopamine receptor subtypes. Our findings provide evidence that dopaminergic neurotransmission plays a central role in regulating HPC-PFC oscillatory dynamics, specifically promoting synchronization in slow-frequency oscillations.