Hippocampal-neocortical interactions sharpen over time for predictive actions.

When an action is familiar, we are able to anticipate how it will change the state of the world. These expectations can result from retrieval of action-outcome associations in the hippocampus and the reinstatement of anticipated outcomes in visual cortex. How does this role for the hippocampus in action-based prediction change over time? We use high-resolution fMRI and a dual-training behavioral paradigm to examine how the hippocampus interacts with visual cortex during predictive and nonpredictive actions learned either three days earlier or immediately before the scan. Just-learned associations led to comparable background connectivity between the hippocampus and V1/V2, regardless of whether actions predicted outcomes. However, three-day-old associations led to stronger background connectivity and greater differentiation between neural patterns for predictive vs. nonpredictive actions. Hippocampal prediction may initially reflect indiscriminate binding of co-occurring events, with action information pruning weaker associations and leading to more selective and accurate predictions over time.

当某一动作为人所熟悉时，我们便能预判其将如何改变世界的状态。这类预判可源于对海马体（hippocampus）中动作-结果关联的提取，以及视觉皮层（visual cortex）中对预期结果的重现。那么，海马体在基于动作的预测中所扮演的这一角色，会随时间推移发生怎样的变化？本研究采用高分辨率功能磁共振成像（high-resolution fMRI）与双训练行为范式（dual-training behavioral paradigm），探究在扫描前3天或扫描即刻习得的预测性与非预测性动作执行过程中，海马体与视觉皮层的交互模式。刚习得的关联会使海马体与V1/V2间的背景连通性处于相当水平，无论该动作是否对结果具有预测性。但对于已习得3天的关联而言，其海马体与V1/V2间的背景连通性更强，且预测性与非预测性动作对应的神经模式间的区分度也更高。海马体介导的预测或许最初仅表现为对共发事件的无差别绑定，后续动作信息会弱化较弱的关联，最终实现更具选择性且更为精准的预测。