Partial Adaptation to the Value Range in the Macaque Orbitofrontal Cortex
Partial Adaptation to the Value Range in the Macaque Orbitofrontal Cortex
复制标题
DOI：
10.1523/jneurosci.2279-18.2019
复制
发表时间：
2019-05-01
影响因子：
5.3
通讯作者：
Padoa-Schioppa, Camillo
中科院分区：
文献类型：
--
作者：
Conen, Katherine E.;Padoa-Schioppa, Camillo
不同行为背景下可供选择的价值观可能会有很大差异。为了补偿这种可变性，经济决策背后的神经元回路经历了适应。在眶额皮层（OFC），神经元以准线性方式编码提供和选择商品的主观价值。以往的实验发现，当取值范围较宽时，编码的增益较低。然而，OFC神经元适应的参数仍然不清楚。此外，以前的研究没有检查神经元反应的累加变化。计算的考虑表明，这些因素可以直接影响选择行为。在这里，我们研究了OFC神经元如何适应数值范围的变化。我们记录了两只雄性恒河猴在果汁选择任务。每次会议分为两组试验。在每个区块中，果汁在设定的值范围内提供，并且范围在区块之间变化。跨块，神经元的反应适应最大值和最小值，但只有部分。结果，最小神经活动在某些值范围内相对于其他值范围升高。通过对线性决策模型的模拟，我们发现，增加最小响应会增加选择的可变性，从而降低预期收益。这种效应是由具有正编码和负编码的细胞之间的平衡调节的。这两个群体的存在导致了价值范围和选择效能之间的非单调关系，使得在中间价值范围内的决策的预期收益最高。
Values available for choice in different behavioral contexts can vary immensely. To compensate for this variability, neuronal circuits underlying economic decisions undergo adaptation. In orbitofrontal cortex (OFC), neurons encode the subjective value of offered and chosen goods in a quasilinear way. Previous experiments found that the gain of the encoding is lower when the value range is wider. However, the parameters OFC neurons adapted to remained unclear. Furthermore, previous studies did not examine additive changes in neuronal responses. Computational considerations indicate that these factors can directly impact choice behavior. Here we investigated how OFC neurons adapt to changes in the value range. We recorded from two male rhesus monkeys during a juice choice task. Each session was divided into two blocks of trials. In each block, juices were offered within a set range of values, and ranges changed between blocks. Across blocks, neuronal responses adapted to both the maximum and the minimum value, but only partially. As a result, the minimum neural activity was elevated in some value ranges relative to others. Through simulation of a linear decision model, we showed that increasing the minimum response increases choice variability, lowering the expected payoff. This effect is modulated by the balance between cells with positive and negative encoding. The presence of these two populations induces a non-monotonic relationship between the value range and choice efficacy, such that the expected payoff is highest for decisions in an intermediate value range.