Departments of Philosophy, Neuroscience, and Economics, Columbia University, New York, New York 10027
Departments of Neuroscience, Psychology, and Marketing, University of Pennsylvania, Philadelphia, Pennsylvania 19104.
J Neurosci. 2021 Mar 24;41(12):2703-2712. doi: 10.1523/JNEUROSCI.0305-20.2020. Epub 2021 Feb 3.
Animals engage in routine behavior to efficiently navigate their environments. This routine behavior may be influenced by the state of the environment, such as the location and size of rewards. The neural circuits tracking environmental information and how that information impacts decisions to deviate from routines remain unexplored. To investigate the representation of environmental information during routine foraging, we recorded the activity of single neurons in posterior cingulate cortex (PCC) in 2 male monkeys searching through an array of targets in which the location of rewards was unknown. Outside the laboratory, people and animals solve such traveling salesman problems by following routine traplines that connect nearest-neighbor locations. In our task, monkeys also deployed traplining routines; but as the environment became better known, they deviate from them despite the reduction in foraging efficiency. While foraging, PCC neurons tracked environmental information but not reward and predicted variability in the pattern of choices. Together, these findings suggest that PCC may mediate the influence of information on variability in choice behavior. Many animals seek information to better guide their decisions and update behavioral routines. In our study, subjects visually searched through a set of targets on every trial to gather two rewards. Greater amounts of information about the distribution of rewards predicted less variability in choice patterns, whereas smaller amounts predicted greater variability. We recorded from the posterior cingulate cortex, an area implicated in the coding of reward and uncertainty, and discovered that these neurons signaled the expected information about the distribution of rewards instead of signaling expected rewards. The activity in these cells also predicted the amount of variability in choice behavior. These findings suggest that the posterior cingulate helps direct the search for information to augment routines.
动物会进行常规行为，以有效地在环境中导航。这种常规行为可能会受到环境状态的影响，例如奖励的位置和大小。跟踪环境信息的神经回路以及该信息如何影响偏离常规行为的决策的神经回路仍未被探索。为了研究常规觅食过程中的环境信息表示，我们记录了 2 只雄性猴子在后扣带皮层（PCC）中单个神经元的活动，这些猴子在一个目标阵列中搜索，其中奖励的位置是未知的。在实验室之外，人类和动物通过遵循连接最近邻居位置的常规追踪线来解决此类旅行商问题。在我们的任务中，猴子也会部署追踪线常规；但是，随着环境变得更加熟悉，尽管觅食效率降低，它们还是会偏离这些常规。在觅食过程中，PCC 神经元跟踪环境信息，但不跟踪奖励，并预测选择模式的可变性。这些发现表明，PCC 可能介导信息对选择行为可变性的影响。许多动物会寻求信息以更好地指导他们的决策并更新行为常规。在我们的研究中，被试者在每次试验中都会通过视觉搜索一组目标以收集两个奖励。有关奖励分布的信息量越大，预测的选择模式的可变性就越小，而信息量越小，则可变性越大。我们从后扣带皮层记录了电活动，该区域与奖励和不确定性的编码有关，发现这些神经元发出了有关奖励分布的预期信息，而不是发出了预期奖励的信号。这些细胞的活动也预测了选择行为的可变性。这些发现表明，后扣带皮层有助于引导对信息的搜索以增强常规。
