Department of Psychology, Program in Neuroscience, The Florida State University, Tallahassee, FL 32306, USA.
Physiol Behav. 2010 Mar 3;99(3):324-33. doi: 10.1016/j.physbeh.2009.11.008. Epub 2009 Nov 26.
The influence of temperature on taste cues and the ability to discriminate and learn about different temperatures of foods are important factors regulating ingestion. The goal of this research was to demonstrate that thermal orosensory input can serve as a salient stimulus to guide ingestive behavior in the rat, and also that it interacts with gustatory input during choice and conditioned aversion experiments. A novel apparatus with Peltier refrigerators was used to control the temperature of solutions in 10-min, 2-bottle tests. It was determined that naive rats preferred cold water (10 degrees C) to warm water (40 degrees ). When cold water was paired with a toxic LiCl injection, rats avoided cold water and drank warm water, thus demonstrating that cold water could serve as the conditioned stimulus in a conditioned temperature aversion. Rats conditioned against cold water could discriminate 10 degrees C water from 16 degrees C water, but not from 13 degrees C water, thus showing an ability to discriminate orosensory thermal cues to within 3-6 degrees C. Rats also generalized conditioned aversions from cold water to cold saccharin and cold sucrose solutions. However, if rats were conditioned against a compound taste and thermal stimulus (10 degrees C, 0.125% saccharin), the rats could distinguish and avoid each component individually, i.e., by avoiding cold water or warm saccharin. Finally, daily 2-bottle extinction tests were used to assess the strength of aversions conditioned against a taste cue (0.25 M sucrose), a thermal cue (10 degrees C water), or the combination. Aversions to taste or temperature alone persisted for 7-14 days of extinction testing, but the combined taste-temperature aversion was stronger and did not extinguish after 20 days of extinction testing. These results demonstrate that temperature can serve as a salient cue in conditioned aversions that affect ingestion independent of taste cues or by potentiating taste cues.
温度对味觉线索以及辨别和了解不同食物温度的能力的影响是调节摄食的重要因素。本研究的目的是证明热味觉输入可以作为指导大鼠摄食行为的显著刺激，并且它在选择和条件性厌恶实验中与味觉输入相互作用。使用带有珀耳帖致冷器的新型设备来控制 10 分钟、2 瓶测试中溶液的温度。结果表明，未接受过训练的大鼠更喜欢冷水（10°C）而不是温水（40°C）。当冷水与有毒的 LiCl 注射配对时，大鼠回避冷水并饮用温水，这表明冷水可以作为条件性温度厌恶的条件刺激。对冷水产生条件性厌恶的大鼠可以区分 10°C 的水和 16°C 的水，但不能区分 13°C 的水，因此表明它们能够辨别口腔感觉的热线索，精度在 3-6°C 之间。大鼠还将条件性厌恶从冷水泛化到冷蔗糖和冷蔗糖溶液。然而，如果大鼠对复合味觉和热刺激（10°C，0.125% 蔗糖）进行条件化，则大鼠可以单独区分和避免每个成分，即通过避免冷水或温蔗糖。最后，使用每日 2 瓶消退测试来评估对味觉线索（0.25 M 蔗糖）、热线索（10°C 水）或两者的组合产生的厌恶的强度。对味觉或温度的厌恶在 7-14 天的消退测试中持续存在，但组合的味觉-温度厌恶更强，在 20 天的消退测试后并未消除。这些结果表明，温度可以作为影响摄食的条件性厌恶的显著线索，而不依赖于味觉线索或增强味觉线索。
