Content-based Dissociation of Hippocampal Involvement in Prediction
Content-based Dissociation of Hippocampal Involvement in Prediction
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DOI：
10.1162/jocn_a_01509
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发表时间：
2020-03-01
影响因子：
3.2
通讯作者：
Turk-Browne, Nicholas B.
中科院分区：
文献类型：
--
作者：
Kok, Peter;Rait, Lindsay I.;Turk-Browne, Nicholas B.
最近的研究表明，海马体的一个关键功能是预测未来。这被认为取决于它在时间和空间上绑定输入的能力，以及基于部分线索检索即将到来或丢失的输入的能力。与此相一致的是，先前的研究揭示了海马体中与复杂视觉对象（如分形和抽象形状）相关的预测信号。这种解释的隐含意义是，海马体中的这些计算反映了适用于不同类型和模式的刺激的域一般过程。另一种说法是海马体在预测处理中扮演着更特定领域的角色，被预测的刺激类型决定了它的参与程度。为了调查这一点，我们比较了海马反应听觉线索预测抽象的形状（实验1）与定向光栅（实验2）。我们使用高分辨率fMRI测量了男性和女性人类参与者的大脑活动，并结合反向编码模型来重建形状和方向信息。我们的研究结果表明，形状和方向的期望在海马体中引起不同的表征。对于复杂的形状，海马体代表了预期的形状，可能是自上而下预测的来源。相比之下，对于简单的光栅，海马体只代表意想不到的方向，更让人联想到预测错误。我们讨论了几个潜在的解释，这种基于内容的分离海马功能，得出的结论是，预测处理的海马的计算作用可能取决于刺激的性质和复杂性。
Recent work suggests that a key function of the hippocampus is to predict the future. This is thought to depend on its ability to bind inputs over time and space and to retrieve upcoming or missing inputs based on partial cues. In line with this, previous research has revealed prediction-related signals in the hippocampus for complex visual objects, such as fractals and abstract shapes. Implicit in such accounts is that these computations in the hippocampus reflect domain-general processes that apply across different types and modalities of stimuli. An alternative is that the hippocampus plays a more domain-specific role in predictive processing, with the type of stimuli being predicted determining its involvement. To investigate this, we compared hippocampal responses to auditory cues predicting abstract shapes (Experiment 1) versus oriented gratings (Experiment 2). We measured brain activity in male and female human participants using high-resolution fMRI, in combination with inverted encoding models to reconstruct shape and orientation information. Our results revealed that expectations about shape and orientation evoked distinct representations in the hippocampus. For complex shapes, the hippocampus represented which shape was expected, potentially serving as a source of top-down predictions. In contrast, for simple gratings, the hippocampus represented only unexpected orientations, more reminiscent of a prediction error. We discuss several potential explanations for this content-based dissociation in hippocampal function, concluding that the computational role of the hippocampus in predictive processing may depend on the nature and complexity of stimuli.