Kadohisa M, Rolls E T, Verhagen J V
University of Oxford, Department of Experimental Psychology, South Parks Road, Oxford OX1 3UD, UK.
Neuroscience. 2004;127(1):207-21. doi: 10.1016/j.neuroscience.2004.04.037.
The primate orbitofrontal cortex is a site of convergence of information from primary taste, olfactory and somatosensory cortical areas. We describe the discovery of a population of single neurons in the macaque orbitofrontal cortex that responds to the temperature of a liquid in the mouth. The temperature stimuli consisted of water at 10 degrees C, 23 degrees C, 37 degrees C and 42 degrees C. Twenty-six of the 1149 neurons analyzed (2.3%) responded to oral temperature. The tuning profiles of the neurons to temperature showed that some of the neurons had graded responses to increasing temperature (27%), others responded to cold (10 degrees C) stimuli (27%), and others were tuned to temperature (46%). The neuronal responses were also measured to taste stimuli, viscosity stimuli (carboxymethyl-cellulose in the range 1-10,000 cP), and capsaicin (10 microM). Of 70 neurons with responses to any of these stimuli, 7.1% were unimodal temperature; 11.3% were temperature and taste-sensitive; 7.1% were temperature and viscosity-sensitive; and 11.3% were temperature, taste and viscosity sensitive. Capsaicin activated 15.7% of the population of responsive neurons tested. These results provide the first evidence of how the temperature of what is in the mouth is represented at the neuronal level in the orbitofrontal cortex and the first evidence for any primate cortical area that in some cases this information converges onto single neurons with inputs produced by other sensory properties of food, including taste and texture. The results provide a basis for understanding how particular combinations of oral temperature, taste, and texture can influence the palatability of foods.
灵长类动物的眶额皮质是来自初级味觉、嗅觉和体感皮质区域的信息汇聚的部位。我们描述了在猕猴眶额皮质中发现的一群对口腔中液体温度有反应的单个神经元。温度刺激由10摄氏度、23摄氏度、37摄氏度和42摄氏度的水组成。在分析的1149个神经元中，有26个（2.3%）对口腔温度有反应。这些神经元对温度的调谐曲线表明，一些神经元对温度升高有分级反应（27%），另一些对冷刺激（10摄氏度）有反应（27%），还有一些则对温度进行了调谐（46%）。还测量了这些神经元对味觉刺激、粘度刺激（1-10000厘泊范围内的羧甲基纤维素）和辣椒素（10微摩尔）的反应。在对这些刺激中的任何一种有反应的70个神经元中，7.1%是单峰温度敏感型；11.3%对温度和味觉敏感；7.1%对温度和粘度敏感；11.3%对温度、味觉和粘度敏感。辣椒素激活了所测试的有反应神经元群体的15.7%。这些结果首次证明了口腔中物质的温度在眶额皮质的神经元水平上是如何被表征的，也是首次证明在某些情况下，这种信息会汇聚到单个神经元上，这些神经元还接收由食物的其他感官特性（包括味道和质地）产生的输入。这些结果为理解口腔温度、味道和质地的特定组合如何影响食物的适口性提供了基础。
