We recently advanced a rodent homologue for the reward-specific, event-related potential component observed in humans known as the Reward Positivity. We sought to determine the cortical source of this signal in mice to further test the nature of this homology. While similar reward-related cortical signals have been identified in rats, these recordings were all performed in cingulate gyrus. Given the value-dependent nature of this event, we hypothesized that more ventral prelimbic and infralimbic areas also contribute important variance to this signal. Depth probes assessed local field activity in 29 mice (15 males) while they completed multiple sessions of a probabilistic reinforcement learning task. Using a priori regions of interest, we demonstrated that the depth of recording in the cortical midline significantly correlated with the size of reward-evoked delta band spectral activity as well as the single trial correlation between delta power and reward prediction error. These findings provide important verification of the validity of this translational biomarker of reward responsiveness, learning, and valuation.

我们最近提出了一种啮齿动物同源物，用于在人类中观察到的奖励特异性、与事件相关的潜在成分，称为奖励积极性。我们试图确定小鼠中该信号的皮质来源，以进一步测试这种同源性的性质。虽然在大鼠中发现了类似的与奖励相关的皮层信号，但这些记录都是在扣带回中进行的。考虑到该事件的值依赖性质，我们假设更多的腹侧前边缘和下边缘区域也对该信号产生重要的方差。深度探针评估了 29 只小鼠（15 只雄性）的局部场活动，同时它们完成了多次概率强化学习任务。使用先验感兴趣区域，我们证明了皮质中线的记录深度与奖励诱发的增量带频谱活动的大小以及增量功率和奖励预测误差之间的单次试验相关性显着相关。这些发现为奖励反应、学习和评价的转化生物标志物的有效性提供了重要验证。