IFM-Biology, Linköping University, 581 83 Linköping, Sweden.
Biol Lett. 2021 Feb;17(2):20200790. doi: 10.1098/rsbl.2020.0790. Epub 2021 Feb 3.
Red Junglefowl () were selected for divergent levels of fear of humans during eight generations, causing the selection lines to differ in fear levels as well as in the proportional brain and cerebellum masses. Birds from the two lines were then crossed to obtain an F3 intercross in order to study the correlations between brain mass and fear learning. We exposed 105 F3-animals individually to a fear habituation and memory test at 8 days of age, where the reactions to repeated light flashes were assessed on 2 consecutive days. After culling, the absolute and relative sizes of each of four brain regions were measured. Stepwise regression was used to analyse the effects of the size of each brain region on habituation and memory. There were no effects of any brain region on the habituation on day one. However, birds with a larger absolute size of cerebellum had significantly reduced reactions to the fearful stimuli on day two, indicating a better memory of the stimuli. No other regions had significant effects. We conclude that increased cerebellum size may have been important in facilitating chicken domestication, allowing them to adapt to a life with humans.
红原鸡（）在 8 个世代中被选择具有不同程度的对人类的恐惧，导致选择系在恐惧水平以及大脑和小脑的比例质量上存在差异。然后将来自这两个系的鸟类杂交，以获得 F3 杂交系，以便研究大脑质量与恐惧学习之间的相关性。我们在 8 天大时单独对 105 只 F3 动物进行了恐惧习惯化和记忆测试，在连续两天评估了对重复闪光的反应。淘汰后，测量了四个脑区的每个脑区的绝对和相对大小。逐步回归用于分析每个脑区大小对习惯化和记忆的影响。没有任何脑区对第一天的习惯化有影响。然而，具有更大的绝对小脑大小的鸟类在第二天对恐惧刺激的反应明显减少，表明对刺激的记忆更好。没有其他区域有显著影响。我们得出的结论是，小脑大小的增加可能对鸡的驯化很重要，使它们能够适应与人类一起的生活。
