Oral and Maxillofacial Radiology, Applied Oral Sciences, Faculty of Dentistry, The University of Hong Kong, Hong Kong SAR, China.
Oral and Maxillofacial Radiology, Applied Oral Sciences, Faculty of Dentistry, The University of Hong Kong, Hong Kong SAR, China; Department of Oral and Maxillofacial Radiology, Tokyo Dental College, 2-9-18, Misakicho, Chiyoda-ku, Tokyo, 101-0061, Japan.
Neuroimage. 2018 Apr 1;169:189-199. doi: 10.1016/j.neuroimage.2017.12.034. Epub 2017 Dec 14.
The primary dimensions of taste are affective value, intensity and quality. Numerous studies have reported the role of the insula in evaluating these dimensions of taste; however, the results were inconsistent. Therefore, in the current study, we performed meta-analyses of published data to identify locations consistently activated across studies and evaluate whether different regions of the human brain could be responsible for processing different dimensions of taste. Meta-analyses were performed on 39 experiments, with 846 total healthy subjects (without psychiatric/neurological disorders) in 34 studies reporting whole-brain results. The aim was to establish the activation likelihood estimation (ALE) of taste-mediated regional activation across the whole brain. Apart from one meta-analysis for all studies in general, three analyses were performed to reveal the clusters of activation that were attributable to processing the affective value (data from 323 foci), intensity (data from 43 foci) and quality (data from 45 foci) of taste. The ALE revealed eight clusters of activation outside the insula for processing affective value, covering the middle and posterior cingulate, pre-/post-central gyrus, caudate and thalamus. The affective value had four clusters of activation (two in each hemisphere) in the insula. The intensity and quality activated only the insula, each with one cluster on the right. The concurrence between studies was moderate; at best, 53% of the experiments contributed to the significant clusters attributable to the affective value, 60% to intensity and 50% to quality. The affective value was processed bilaterally in the anterior to middle insula, whereas intensity was processed in the right antero-middle insula, and quality was processed in the right middle insula. The right middle dorsal insula was responsible for processing both the affective value and quality of taste. The exploratory analysis on taste quality did not have a significant result if the studies using liquid food stimuli were excluded. Results from the meta-analyses on studies involving the oral delivery of liquid tastants or liquid food stimuli confirmed that the insula is involved in processing all three dimensions of taste. More experimental studies are required to investigate whether brain activations differ between liquid tastants and food. The coordinates of activated brain areas and brain maps are provided to serve as references for future taste/food studies.
味觉的主要维度包括情感价值、强度和质量。许多研究报告了脑岛在评估这些味觉维度中的作用；然而，结果并不一致。因此，在目前的研究中，我们对已发表的数据进行了荟萃分析，以确定在研究中一致激活的位置，并评估人脑的不同区域是否可以负责处理不同的味觉维度。对 39 项实验进行了荟萃分析，涉及 34 项报告全脑结果的研究中的 846 名健康受试者（无精神/神经障碍）。目的是确定整个大脑中味觉介导的区域激活的激活可能性估计（ALE）。除了对一般所有研究进行的一项荟萃分析外，还进行了三项分析以揭示归因于处理味觉情感价值（来自 323 个焦点的数据）、强度（来自 43 个焦点的数据）和质量（来自 45 个焦点的数据）的激活聚类。ALE 显示了处理情感价值的 8 个岛外激活聚类，涵盖了中后扣带、前/后中央回、尾状核和丘脑。情感价值在岛中有四个激活聚类（每个半球两个）。强度和质量仅激活岛，右侧各有一个聚类。研究之间的一致性中等；在最佳情况下，53%的实验有助于归因于情感价值的显著聚类，60%的实验有助于强度聚类，50%的实验有助于质量聚类。情感价值在岛的前到中侧双侧处理，而强度在右侧前中岛处理，质量在右侧中岛处理。右侧中背侧岛负责处理味觉的情感价值和质量。如果排除使用液体食物刺激的研究，味觉质量的探索性分析没有显著结果。涉及液体味觉剂或液体食物刺激口腔传递的研究的荟萃分析结果证实，岛参与处理味觉的所有三个维度。需要更多的实验研究来调查液体味觉剂和食物之间的大脑激活是否不同。提供激活脑区的坐标和脑图，以供未来味觉/食物研究参考。
