Suen Justin Long Kiu, Yeung Andy Wai Kan, Wu Ed X, Leung Wai Keung, Tanabe Hiroki C, Goto Tazuko K
Faculty of Dentistry, The University of Hong Kong, Hong Kong, China.
Department of Oral and Maxillofacial Radiology, Tokyo Dental College, 2-9-18, Kanda-Misakicho, Chiyoda-ku, Tokyo 101-0061, Japan.
Foods. 2021 Aug 29;10(9):2034. doi: 10.3390/foods10092034.
The anterior insula and rolandic operculum are key regions for flavour perception in the human brain; however, it is unclear how taste and congruent retronasal smell are perceived as flavours. The multisensory integration required for sour flavour perception has rarely been studied; therefore, we investigated the brain responses to taste and smell in the sour flavour-processing network in 35 young healthy adults. We aimed to characterise the brain response to three stimulations applied in the oral cavity-sour taste, retronasal smell of mango, and combined flavour of both-using functional magnetic resonance imaging. Effective connectivity of the flavour-processing network and modulatory effect from taste and smell were analysed. Flavour stimulation activated middle insula and olfactory tubercle (primary taste and olfactory cortices, respectively); anterior insula and rolandic operculum, which are associated with multisensory integration; and ventrolateral prefrontal cortex, a secondary cortex for flavour perception. Dynamic causal modelling demonstrated that neural taste and smell signals were integrated at anterior insula and rolandic operculum. These findings elucidated how neural signals triggered by sour taste and smell presented in liquid form interact in the brain, which may underpin the neurobiology of food appreciation. Our study thus demonstrated the integration and synergy of taste and smell.
前脑岛和中央前回岛盖是人类大脑中味觉感知的关键区域；然而，目前尚不清楚味觉和与之相符的鼻后嗅觉是如何被感知为味道的。酸味感知所需的多感官整合很少被研究；因此，我们调查了35名年轻健康成年人在酸味处理网络中对味觉和嗅觉的大脑反应。我们旨在使用功能磁共振成像来描述大脑对三种施加于口腔的刺激——酸味、芒果的鼻后嗅觉以及两者的混合味道——的反应。分析了味道处理网络的有效连接性以及味觉和嗅觉的调节作用。味道刺激激活了脑岛中部和嗅结节（分别为主要味觉和嗅觉皮层）；与多感官整合相关的前脑岛和中央前回岛盖；以及腹外侧前额叶皮层，这是一个用于味道感知的二级皮层。动态因果模型表明，神经味觉和嗅觉信号在前脑岛和中央前回岛盖处整合。这些发现阐明了由酸味和以液体形式呈现的嗅觉触发的神经信号在大脑中是如何相互作用的，这可能是食物鉴赏神经生物学的基础。因此，我们的研究证明了味觉和嗅觉的整合与协同作用。
