Shipley M T, Geinisman Y
Brain Res Bull. 1984 Mar;12(3):221-6. doi: 10.1016/0361-9230(84)90049-2.
Flavor perception requires the neural integration of olfactory, gustatory and, possibly, visceral afferent information. Presently, it is not known where, or how this integration takes place in the brain. Neuroanatomical data presented here suggest that pathways subserving these sensory modalities converge in mouse insular cortex after surprisingly few synaptic relays. Orthograde transport of wheat germ agglutinin conjugated to horseradish peroxidase (WGA-HRP) was used to label main olfactory bulb (MOB) efferents. A projection into layer I of insular cortex was present in every case. Bulb transections were made to provoke anterograde degeneration and EM analysis confirmed that the olfactory projection to insular cortex was a terminal pathway. WGA-HRP injections in the MOB-recipient zone of insular cortex resulted in ortho and retrograde labeling of ascending and descending gustatory-visceral afferent pathways. It is concluded that in the mouse, there is a remarkably direct convergence of olfactory and gustatory-visceral sensory pathways in insular cortex. Together with the descending connections from insular cortex to the amygdala and to brainstem autonomic structures, it is possible that the cortical integration of olfactory and gustatory-visceral information could modulate mechanisms involved in food selection and autonomic reactions relating to the chemical senses. Basic mechanisms subserving flavor perception might be usefully modelled in mouse insular cortex.
味觉感知需要嗅觉、味觉以及可能的内脏传入信息的神经整合。目前，尚不清楚这种整合在大脑中的何处以及如何发生。此处呈现的神经解剖学数据表明，在经过极少的突触中继后，服务于这些感觉模式的通路在小鼠岛叶皮质汇聚。将与辣根过氧化物酶结合的小麦胚芽凝集素（WGA-HRP）进行顺行运输，用于标记主嗅球（MOB）传出纤维。在每种情况下，都存在向岛叶皮质I层的投射。进行嗅球横切以引发顺行性变性，电镜分析证实向岛叶皮质的嗅觉投射是一条终末通路。在岛叶皮质的MOB接受区注射WGA-HRP导致味觉-内脏传入通路的升支和降支出现顺行和逆行标记。得出的结论是，在小鼠中，嗅觉和味觉-内脏感觉通路在岛叶皮质有非常直接的汇聚。连同从岛叶皮质到杏仁核和脑干自主神经结构的下行连接，嗅觉和味觉-内脏信息的皮质整合有可能调节与食物选择以及与化学感觉相关的自主反应有关的机制。服务于味觉感知的基本机制可能在小鼠岛叶皮质中得到有效建模。
