Department of Psychobiology, Institute of Neurosciences, Center for Biomedical Research (CIBM), University of Granada, Parque Tecnológico de la Salud (PTS), Avda del Conocimiento, s/n, Armilla, 18016, Granada, Spain.
Laboratory of Neuroscience, Department of Psychology, University of Oviedo, Oviedo, Spain.
Behav Brain Funct. 2023 Feb 3;19(1):2. doi: 10.1186/s12993-023-00206-x.
Novel flavors elicit a cautious neophobic response which is attenuated as the flavor becomes familiar and safe. The attenuation of neophobia reveals the formation of a safe memory. Previous lesion studies in rats have reported that basolateral amygdala integrity is required for taste neophobia, but not neophobia to flavor, i.e., taste linked to an odorous component. Accordingly, immunohistochemical analyses show that novel tastes induced higher basolateral amygdala activity when compared to familiar ones. However, a different role of basolateral amygdala in flavor attenuation of neophobia is suggested by lesion studies using a vinegar solution. Studies assessing basolateral amygdala activity during flavor attenuation of neophobia are lacking. Thus, we quantified cytochrome oxidase as an index of basolateral amygdala activity along the first and second vinegar exposures in order to assess flavor neophobia and attenuation of neophobia.
We exposed adult male Wistar rats either once or twice to a 3% cider vinegar solution or water, and compared the basolateral amygdala, piriform cortex and caudate putamen brain metabolic activity using cytochrome c-oxidase histochemistry.
We found increased flavor intake and cytochrome c-oxidase histochemistry activity during the second exposure in basolateral amygdala, but not in the piriform cortex and caudate/putamen.
The main finding of the study is that BLA metabolic activity was higher in the group exposed to a familiar vinegar solution than in the groups exposed to either water or a novel vinegar solution.
新的味道会引起谨慎的新异恐惧症反应，随着味道变得熟悉和安全，这种反应会减弱。新异恐惧症的减弱揭示了安全记忆的形成。先前的大鼠病变研究报告称，外侧杏仁核的完整性是味觉新异恐惧症所必需的，但不是对味道的新异恐惧症，即与气味成分相关的味道。因此，免疫组织化学分析表明，与熟悉的味道相比，新的味道会引起更高的外侧杏仁核活性。然而，使用醋溶液的病变研究表明，外侧杏仁核在风味新异恐惧症减弱中的作用不同。缺乏评估风味新异恐惧症减弱过程中外侧杏仁核活动的研究。因此，我们量化了细胞色素氧化酶作为外侧杏仁核活性的指标，以评估风味新异恐惧症和新异恐惧症的减弱。
我们让成年雄性 Wistar 大鼠一次性或两次暴露于 3%的苹果醋溶液或水中，并使用细胞色素 c-氧化酶组织化学比较外侧杏仁核、梨状皮层和尾壳核的大脑代谢活性。
我们发现，在第二次暴露于外侧杏仁核时，风味摄入量增加，细胞色素 c-氧化酶组织化学活性增加，但在梨状皮层和尾壳核/纹状体中没有增加。
该研究的主要发现是，与暴露于水或新的醋溶液的组相比，暴露于熟悉的醋溶液的组中 BLA 的代谢活性更高。
