Department of Neurobiology, University of California San Diego, La Jolla, CA, USA.
Center for Neural Circuits and Behavior, University of California San Diego, La Jolla, CA, USA.
Sci Adv. 2023 Dec;9(48):eadj4897. doi: 10.1126/sciadv.adj4897. Epub 2023 Nov 29.
Animals use past experience to guide future choices. The integration of experiences typically follows a hyperbolic, rather than exponential, decay pattern with a heavy tail for distant history. Hyperbolic integration affords sensitivity to both recent environmental dynamics and long-term trends. However, it is unknown how the brain implements hyperbolic integration. We found that mouse behavior in a foraging task showed hyperbolic decay of past experience, but the activity of cortical neurons showed exponential decay. We resolved this apparent mismatch by observing that cortical neurons encode history information with heterogeneous exponential time constants that vary across neurons. A model combining these diverse timescales recreated the heavy-tailed, hyperbolic history integration observed in behavior. In particular, the time constants of retrosplenial cortex (RSC) neurons best matched the behavior, and optogenetic inactivation of RSC uniquely reduced behavioral history dependence. These results indicate that behavior-relevant history information is maintained across multiple timescales in parallel and that RSC is a critical reservoir of information guiding decision-making.
动物利用过去的经验来指导未来的选择。经验的整合通常遵循双曲而非指数衰减模式，对于遥远的历史具有重尾。双曲整合使大脑对近期环境动态和长期趋势都具有敏感性。然而，大脑如何实现双曲整合尚不清楚。我们发现，老鼠在觅食任务中的行为表现出过去经验的双曲衰减，但大脑皮层神经元的活动表现出指数衰减。我们通过观察到皮层神经元以异质的指数时间常数来编码历史信息，这些时间常数在神经元之间变化，从而解决了这种明显的不匹配。一个结合了这些不同时间尺度的模型重现了在行为中观察到的长尾双曲历史整合。特别是，后扣带回皮层（RSC）神经元的时间常数与行为最匹配，而光遗传学失活 RSC 则独特地降低了行为对历史的依赖性。这些结果表明，与行为相关的历史信息在多个时间尺度上并行维持，并且 RSC 是指导决策的关键信息库。
