Aronov Dmitriy, Nevers Rhino, Tank David W
Princeton Neuroscience Institute, Princeton University, Princeton, New Jersey 08544, USA.
Nature. 2017 Mar 29;543(7647):719-722. doi: 10.1038/nature21692.
During spatial navigation, neural activity in the hippocampus and the medial entorhinal cortex (MEC) is correlated to navigational variables such as location, head direction, speed, and proximity to boundaries. These activity patterns are thought to provide a map-like representation of physical space. However, the hippocampal-entorhinal circuit is involved not only in spatial navigation, but also in a variety of memory-guided behaviours. The relationship between this general function and the specialized spatial activity patterns is unclear. A conceptual framework reconciling these views is that spatial representation is just one example of a more general mechanism for encoding continuous, task-relevant variables. Here we tested this idea by recording from hippocampal and entorhinal neurons during a task that required rats to use a joystick to manipulate sound along a continuous frequency axis. We found neural representation of the entire behavioural task, including activity that formed discrete firing fields at particular sound frequencies. Neurons involved in this representation overlapped with the known spatial cell types in the circuit, such as place cells and grid cells. These results suggest that common circuit mechanisms in the hippocampal-entorhinal system are used to represent diverse behavioural tasks, possibly supporting cognitive processes beyond spatial navigation.
在空间导航过程中，海马体和内侧内嗅皮层（MEC）中的神经活动与导航变量相关，如位置、头部方向、速度以及与边界的接近程度。这些活动模式被认为提供了物理空间的地图式表征。然而，海马 - 内嗅回路不仅参与空间导航，还参与各种记忆引导行为。这种一般功能与专门的空间活动模式之间的关系尚不清楚。调和这些观点的一个概念框架是，空间表征只是一种更普遍的机制的一个例子，该机制用于编码连续的、与任务相关的变量。在这里，我们通过在一项任务中记录海马体和内嗅神经元的活动来测试这一想法，该任务要求大鼠使用操纵杆沿着连续的频率轴操纵声音。我们发现了整个行为任务的神经表征，包括在特定声音频率处形成离散放电场的活动。参与这种表征的神经元与回路中已知的空间细胞类型（如位置细胞和网格细胞）重叠。这些结果表明，海马 - 内嗅系统中的共同回路机制用于表征不同的行为任务，可能支持空间导航之外的认知过程。
