ABSTRACT

The discovery of the role of light exposure for the development of lateralization in domestic chick embryos revolutionized this research field. However, two main issues remain unresolved: (i) while in chicks anatomical light-dependent lateralization is mostly confined to the thalamofugal visual pathway, in pigeons only the tectofugal pathway is lateralized after light exposure. However, no study in either species ever investigated anatomical lateralization in the entopallium, the forebrain station of the tectofugal pathway. (ii) It is now known that lateralization can be observed also in dark-incubated chicks, both at the behavioural and at the Immediate Early Gene-expression level. We hypothesized that lateralization of the tectofugal system may underlie these light-independent effects. To investigate structural lateralization in the tectofugal pathway of dark-incubated chicks, we used parvalbumin (PV) as a marker of a sub population of entopallial neurons, quantifying PV-ir cell densities in the left and right entopallium. We found higher density in the right hemisphere, revealing for the first time anatomical lateralization in entopallium and confirming its potential role in supporting lateralized brain processing in dark-incubated birds. Results are discussed in relation to the possible functional role of PV-ir cells in inhibitory neural functions.

摘要

曝光对于家禽胚胎侧向化发展的作用的发现彻底改变了这一研究领域。然而，两个主要问题仍未解决：（i）在雏鸡中，解剖学上依赖光的侧向化主要局限于丘脑真菌视道，而在鸽子中，暴露后仅将tectofugal途径侧向化。然而，在这两个物种中都没有研究过对睑板腺途径前脑的额叶上皮的解剖学偏侧化研究。（ii）现已知道，在黑暗孵化的雏鸡中，也可以在行为和立即早期基因表达水平上观察到侧向化。我们假设，tectofugal系统的侧向化可能是这些与光无关的作用的基础。为了研究在黑暗孵化的雏鸡的粪铁蛋白的途径中的结构偏侧化，我们使用小白蛋白（PV）作为上皮神经元亚群的标志物，量化了左上皮和右上皮中PV-ir细胞的密度。我们在右半球发现更高的密度，这首次揭示了内皮的解剖学侧偏，并证实了其在支持黑暗孵化鸟类的侧脑化过程中的潜在作用。讨论了有关PV-ir细胞在抑制性神经功能中可能的功能作用的结果。首次揭示了额叶上皮的解剖学偏侧化，并证实了其在支持黑暗孵化鸟类的偏侧化大脑加工中的潜在作用。讨论了有关PV-ir细胞在抑制性神经功能中可能的功能作用的结果。首次揭示了额叶上皮的解剖学偏侧化，并证实了其在支持黑暗孵化鸟类的偏侧化大脑加工中的潜在作用。讨论了有关PV-ir细胞在抑制性神经功能中可能的功能作用的结果。