The role of gustatory cortex in perceptual learning of taste

项目总结 为了适应和生存在自然环境中，动物需要学会辨别预测的感觉刺激 不同的结果。这种能力在感觉输入大量重叠的情况下尤为重要。为 例如，在口味上，其他相似解决方案之间的微小差异可能意味着 吃下毒药，吃上一顿安全的饭。这种被称为知觉学习的现象一直很好 记录了各种物种和感官模式。然而，了解神经平台的机制- 知觉学习背后的可塑性--即大脑如何以可塑性方式编码、概括和辨别大的 重叠刺激的数量--在神经科学研究中仍然是一个巨大的挑战。视觉和视觉方面的研究 听觉系统已经在两个不相互排斥的模型上收敛，1)感觉表示的增强- 2)提高了决策回路解释感官证据以指导行动的能力。Gener- 总之，这两种类型的活动在不同的大脑区域都可以找到，然而这两种类型都可以在初级大脑中找到 味觉皮质，称为味觉岛叶皮质(GC)。这使得品味系统成为测试相对稳定性的理想系统。 这两种模式的贡献。此外，知觉学习背后的可塑性机制仍然存在 目前还不完全清楚，但一些研究表明，神经调节剂多巴胺起到了一定的作用。这条狗- 租金提案将检验以下假设：1)重叠的味觉刺激和相关的感觉的表征-- 小鼠学习知觉辨别任务时GC神经元分离的神经元；2)GC-DA能信号转导 任务学习和表现的可塑性。我将依靠基于品味的两种选择强制选择 (2AFC)训练小鼠辨别混合物中的主要味道。去研究化学感官和 在GC中与决策相关的编码，我将在GC人群中使用慢性双光子和宽视野钙成像 神经元在老鼠学习的过程中。为了分析多巴胺在任务学习和表现中的作用，我将使用选择性 GC多巴胺能轴突损伤和局部化学抑制多巴胺传递联合 钙质成像。这些实验将提供有关味觉加工的重要信息，即神经基础 知觉学习和皮质多巴胺在更广泛的味觉和感觉处理中的作用。

PROJECT SUMMARY To adapt and survive in natural environments, animals need to learn to discriminate sensory stimuli predicting different outcomes. This ability is particularly important in the case of largely overlapping sensory inputs. For example, in taste, small differences between otherwise similar solutions could mean the difference between ingesting a poison and having a safe meal. This phenomenon, known as perceptual learning, has been well documented across species and sensory modalities. However, understanding the mechanisms of neural plas- ticity underlying perceptual learning - i.e. how the brain plastically encodes, generalizes and discriminates large numbers of overlapping stimuli - remains a great challenge in neuroscientific research. Studies in the visual and auditory systems have converged on two non-mutually exclusive models, 1) enhancement of sensory represen- tations and 2) improved ability of decision-making circuits to interpret sensory evidence to guide actions. Gener- ally, these two types of activity are found in different brain areas, however both types can be found in the primary taste cortex, known as the gustatory insular cortex (GC). This makes taste an ideal system to test relative con- tributions of the two models. Additionally, the mechanisms of plasticity underlying perceptual learning remain incompletely understood, but some studies have suggested a role for the neuromodulator, dopamine. The cur- rent proposal will test the hypotheses that 1) representations of overlapping taste stimuli and associated deci- sions by GC neurons separate as mice learn a perceptual discrimination task; 2) GC DAergic signaling mediates plasticity underlying task learning and performance. I will rely on a taste-based two alternative forced choice (2AFC) in which mice are trained to detect the predominant taste in a mixture. To study chemosensory and decision-related coding in GC, I will use chronic 2-photon and widefield calcium imaging in populations of GC neurons as mice learn. To parse the role of dopamine in task learning and performance, I will use selective lesioning of GC dopaminergic axons and local chemogenetic inhibition of dopamine transmission combined with calcium imaging. These experiments will provide important information about taste processing, the neural basis of perceptual learning and the role of cortical dopamine in taste and sensory processing more broadly.