The role of gustatory cortex in perceptual learning of taste

项目摘要 为了适应和生存在自然环境中，动物需要学会区分感官刺激预测 不同的结果。这种能力在感觉输入大量重叠的情况下尤其重要。为 例如，在味道上，其他相似解决方案之间的微小差异可能意味着 吃一顿安全的饭。这种现象被称为知觉学习， 记录了不同物种和感觉方式。然而，了解神经可塑性的机制- 知觉学习的潜在性-即大脑如何可塑性编码，概括和区分大的 重叠刺激的数量-仍然是神经科学研究中的一个巨大挑战。视觉研究和 听觉系统已经集中在两个非相互排斥的模型上，1）感觉表征的增强， 2）提高决策电路解释感官证据以指导行动的能力。Gener- 总之，这两种类型的活动存在于不同的大脑区域，然而，这两种类型都可以在主要的大脑区域中找到。 味觉皮层，称为味觉岛叶皮层（gustatory insular cortex，GC）。这使得味道成为测试相对一致性的理想系统。 两种模式的贡献。此外，知觉学习的可塑性机制仍然存在， 目前尚不完全清楚，但一些研究表明神经调节剂多巴胺的作用。这狗- 租金建议将测试的假设，1）重叠的味觉刺激和相关的决定， 当小鼠学习知觉辨别任务时，GC神经元分离; 2）GC DA能信号传导介导 可塑性潜在的任务学习和性能。我将依靠一种口味为基础的两种选择被迫选择 （2AFC），其中训练小鼠以检测混合物中的主要味道。为了研究化学感应和 由于GC中的决策相关编码，我将在GC人群中使用慢性双光子和宽视野钙成像 神经元的学习能力。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多巴胺能轴突的损伤和多巴胺传递的局部化学发生抑制， 钙显像这些实验将提供有关味觉加工的重要信息， 以及皮层多巴胺在味觉和感觉加工中的作用。

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.