Abstract In the brain, high-order and low-order areas are connected via bottom-up connections (from low-order to high-order areas) and top-down connections (from high-order to low-order areas). While bottom-up signals are thought to be critical in generating perception, functions of top-down signals have not been clearly delineated. One popular theory is that top-down inputs modify the activity of specific cell assemblies to modulate responses to bottom-up inputs. However, a different line of studies proposes that not all top-down inputs are specifically delivered. As the leading theories cannot account for nonspecific top-down inputs, we seek potential functions of nonspecific top-down signals using network models in our study. Our simulation results suggest that top-down inputs can regulate low-order area responses by providing temporal information even without spatial specificity. Specifically, the temporal information in nonspecific top-down inputs can weaken the undesired bottom-up connections, contributing to bottom-up connections’ learning. Further, we found that cortical rhythms (synchronous oscillatory neural responses) are critical in the proposed learning process of bottom-up connections in our model.

中文翻译：

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通过空间非特定自上而下输入的自下而上连接的时间学习

摘要 在大脑中，高阶和低阶区域通过自下而上的连接（从低阶到高阶区域）和自上而下的连接（从高阶到低阶区域）进行连接。虽然自下而上的信号被认为是产生感知的关键，但自上而下的信号的功能尚未明确界定。一种流行的理论是自上而下的输入修改特定细胞组件的活动以调节对自下而上输入的响应。然而，另一类研究提出并非所有自上而下的输入都是专门提供的。由于主流理论无法解释非特定自上而下的输入，我们在研究中使用网络模型寻找非特定自上而下信号的潜在功能。我们的模拟结果表明，即使没有空间特异性，自上而下的输入也可以通过提供时间信息来调节低阶区域响应。具体来说，非特定自上而下输入中的时间信息可以削弱不想要的自下而上连接，有助于自下而上连接的学习。此外，我们发现皮层节律（同步振荡神经反应）在我们模型中提出的自下而上连接的学习过程中至关重要。