Western-style diet impairs stimulus control by food deprivation state cues: Implications for obesogenic environments.
Western-style diet impairs stimulus control by food deprivation state cues: Implications for obesogenic environments.
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DOI：
10.1016/j.appet.2015.05.018
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发表时间：
2015-10
期刊：
影响因子：
5.4
通讯作者：
Davidson TL
中科院分区：
文献类型：
--
作者：
Sample CH;Martin AA;Jones S;Hargrave SL;Davidson TL
在西方和西方化的社会中，大部分人口生活在被认为是“肥胖”的环境中。除其他外，致胖环境的特征是与高可口、高能量密度食物相关的外部线索的高流行率。一个突出的假设认为，这些外部线索成为食欲和饮食行为的强大条件诱发物，它们压倒了维持能量平衡的内部生理机制。本研究探讨了一种学习机制，可能是这种损失的内部相对于外部控制。在实验1中，大鼠提供了听觉线索（外部刺激）和不同程度的食物剥夺（内部刺激），他们可以用来解决一个简单的歧视任务。尽管有明确的可辨别的外部线索，我们发现，剥夺线索获得了大量的条件反射的歧视性控制。实验2发现，与标准食物相比，维持高饱和脂肪和糖的“西式”饮食削弱了食物剥夺线索的辨别控制，但当外部线索也被训练为蔗糖的相关辨别信号时，不会损害学习。因此，吃西式饮食有助于失去对与外部线索相关的食欲行为的内部控制。我们讨论了这种相对失控的食物剥夺信号可能会导致干扰依赖于大脑的学习和记忆过程，形成一个恶性循环的过量摄入，体重增加，并进行性认知能力下降，可能开始在生命的早期。
In western and westernized societies, large portions of the population live in what are considered to be “obesogenic” environments. Among other things, obesogenic environments are characterized by a high prevalence of external cues that are associated with highly palatable, energy-dense foods. One prominent hypothesis suggests that these external cues become such powerful conditioned elicitors of appetitive and eating behavior that they overwhelm the internal, physiological mechanisms that serve to maintain energy balance. The present research investigated a learning mechanism that may underlie this loss of internal relative to external control. In Experiment 1, rats were provided with both auditory cues (external stimuli) and varying levels of food deprivation (internal stimuli) that they could use to solve a simple discrimination task. Despite having access to clearly discriminable external cues, we found that the deprivation cues gained substantial discriminative control over conditioned responding. Experiment 2 found that, compared to standard chow, maintenance on a “western-style” diet high in saturated fat and sugar weakened discriminative control by food deprivation cues, but did not impair learning when external cues were also trained as relevant discriminative signals for sucrose. Thus, eating a western-style diet contributed to a loss of internal control over appetitive behavior relative to external cues. We discuss how this relative loss of control by food deprivation signals may result from interference with hippocampal-dependent learning and memory processes, forming the basis of a vicious-cycle of excessive intake, body weight gain, and progressive cognitive decline that may begin very early in life.