Taste Quality Representation in the Human Brain
Taste Quality Representation in the Human Brain
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DOI：
10.1523/jneurosci.1751-19.2019
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发表时间：
2020-01-29
影响因子：
5.3
通讯作者：
Martin, Alex
中科院分区：
文献类型：
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作者：
Avery, Jason A.;Liu, Alexander G.;Martin, Alex
在哺乳动物的大脑中，脑岛是参与味觉感知的主要皮质底物。最近对啮齿动物的成像研究发现，在脑岛上有一种“味觉”组织，在这种组织中，不同的岛区对五种基本口味中的一种有选择性地做出反应。然而，许多对猴子的研究报告说，味觉皮质神经元对多种口味有广泛的调谐，而味觉不是在离散的空间位置表现出来的。到目前为止，人类的神经成像研究还无法区分这两种模型，尽管这可能是因为迄今为止味觉研究中使用的空间分辨率相对较低。在目前的研究中，我们使用高磁场强度(7特斯拉)下的超高分辨率功能磁共振成像(MRI)研究了人类大脑中味觉的空间表征。在扫描过程中，男性和女性参与者品尝了甜、咸、酸和无味的液体，通过定制的与MRI兼容的味觉传递系统提供。我们的单变量分析显示，所有的味道(与无味的)激活了双侧中岛背侧的初级味觉皮质，但没有一个大脑区域对任何个体的味道表现出一致的偏好。然而，我们的多变量探照灯分析能够可靠地破译这些中脑岛区域以及与影响和奖励有关的大脑区域的不同口味的身份，如纹状体、眶前皮质和杏仁核。这些结果表明，味觉质量并不是在地形图上表现出来的，而是由分布在初级味觉皮质以及参与处理味觉享乐和厌恶特性的区域的种群代码来表示的。
In the mammalian brain, the insula is the primary cortical substrate involved in the perception of taste. Recent imaging studies in rodents have identified a "gustotopic" organization in the insula, whereby distinct insula regions are selectively responsive to one of the five basic tastes. However, numerous studies in monkeys have reported that gustatory cortical neurons are broadly-tuned to multiple tastes, and tastes are not represented in discrete spatial locations. Neuroimaging studies in humans have thus far been unable to discern between these two models, though this may be because of the relatively low spatial resolution used in taste studies to date. In the present study, we examined the spatial representation of taste within the human brain using ultra-high resolution functional magnetic resonance imaging (MRI) at high magnetic field strength (7-tesla). During scanning, male and female participants tasted sweet, salty, sour, and tasteless liquids, delivered via a custom-built MRI-compatible tastant-delivery system. Our univariate analyses revealed that all tastes (vs tasteless) activated primary taste cortex within the bilateral dorsal mid-insula, but no brain region exhibited a consistent preference for any individual taste. However, our multivariate searchlight analyses were able to reliably decode the identity of distinct tastes within those mid-insula regions, as well as brain regions involved in affect and reward, such as the striatum, orbitofrontal cortex, and amygdala. These results suggest that taste quality is not represented topographically, but by a distributed population code, both within primary taste cortex as well as regions involved in processing the hedonic and aversive properties of taste.