This study examined how the medial frontal (MFC) and orbital frontal (OFC) cortices process reward information. We simultaneously recorded local field potentials in the two areas as rats consumed liquid sucrose rewards. Both areas exhibited a 4-8 Hz 'theta' rhythm that was phase locked to the lick cycle. The rhythm tracked shifts in sucrose concentrations and fluid volumes, demonstrating that it is sensitive to differences in reward magnitude. The coupling between the rhythm and licking was stronger in MFC than OFC and varied with response vigor and absolute reward value in the MFC. Spectral analysis revealed zero-lag coherence between the cortical areas, and found evidence for a directionality of the rhythm, with MFC leading OFC. Our findings suggest that consummatory behavior generates simultaneous theta range activity in the MFC and OFC that encodes the value of consumed fluids, with the MFC having a top-down role in the control of consumption.

中文翻译：

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内侧和眶额皮质中的相干 theta 活动编码奖励值

这项研究检查了内侧额叶 (MFC) 和眶额叶 (OFC) 皮质如何处理奖励信息。当大鼠消耗液体蔗糖奖励时，我们同时记录了两个区域的局部场电位。两个区域都表现出 4-8 Hz 的“theta”节奏，该节奏被锁相到舔周期。节奏跟踪蔗糖浓度和液体量的变化，表明它对奖励幅度的差异很敏感。MFC 中节奏和舔舐之间的耦合比 OFC 更强，并且随着 MFC 中的响应强度和绝对奖励值而变化。光谱分析揭示了皮层区域之间的零滞后相干性，并发现了节律方向性的证据，MFC 领先于 OFC。