Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge CB2 3DY, UK.
Eur J Neurosci. 2011 Sep;34(6):1006-17. doi: 10.1111/j.1460-9568.2011.07813.x. Epub 2011 Aug 16.
The development of food preferences contributes to a balanced diet, and involves both innate and learnt factors. By associating flavour cues with the reinforcing properties of the food (i.e. postingestive nutrient cues and innately preferred tastes, such as sweetness), animals acquire individual preferences. How the brain codes and guides selection when the subject has to choose between different palatable foods is little understood. To investigate this issue, we trained common marmoset monkeys (Callithrix jacchus) to respond to abstract visual patterns on a touch-sensitive computer screen to gain access to four different flavoured juices. After preferences were stable, animals received excitotoxic lesions of either the amygdala, the orbitofrontal cortex or the medial prefrontal cortex. Neither the orbitofrontal nor the medial prefrontal cortex lesions affected pre-surgery-expressed flavour preferences or the expression of preferences for novel flavours post-surgery. In contrast, amygdala lesions caused a shift in the preferences for juices expressed pre-surgery such that, post-surgery, juices were chosen according to their overall carbohydrate (simple sugars) content or 'sweetness'. Subsequent tests revealed that amygdala-lesioned animals only expressed juice preferences if they differed in 'sweetness'. Unlike controls, orbitofrontal cortex-lesioned and medial prefrontal cortex-lesioned animals, they were unable to display preferences between juices matched for 'sweetness' i.e. 5% sucrose solutions aromatised with different essential oils. The most parsimonious explanation is that the amygdala contributes to the expression of food preferences based on learnt cues but not those based on an innate preference for sweetness.
食物偏好的发展有助于饮食均衡，涉及先天和后天习得的因素。动物通过将味道线索与食物的强化特性（即食后营养线索和先天喜欢的味道，如甜味）联系起来，获得个体偏好。当主体必须在不同美味的食物之间做出选择时，大脑如何对选择进行编码和引导，目前了解甚少。为了研究这个问题，我们训练普通狨猴（Callithrix jacchus）对触摸敏感的电脑屏幕上的抽象视觉模式做出反应，以获得四种不同口味的果汁。在偏好稳定后，动物接受杏仁核、眶额皮质或内侧前额叶皮质的兴奋性毒性损伤。眶额皮质或内侧前额叶皮质的损伤都不会影响手术前表达的口味偏好，也不会影响手术后对新口味偏好的表达。相比之下，杏仁核损伤导致了手术前表达的果汁偏好的转变，使得手术后，果汁是根据其总碳水化合物（简单糖）含量或“甜度”来选择的。随后的测试表明，杏仁核损伤的动物只有在“甜度”不同时才会表达对果汁的偏好。与对照组、眶额皮质损伤组和内侧前额叶皮质损伤组不同，它们无法在甜度匹配的果汁之间表现出偏好，即 5%蔗糖溶液用不同的精油调味。最合理的解释是，杏仁核有助于基于后天习得的线索表达食物偏好，但不基于对甜味的先天偏好。
