Center for Mind/Brain Sciences, University of Trento, Trento, Italy.
Sci Rep. 2020 Apr 29;10(1):7205. doi: 10.1038/s41598-020-64224-9.
In birds, like in mammals, the hippocampus is particularly sensitive to exposure to novel environments, a function that is based on visual input. Chicks' eyes are placed laterally and their optic fibers project mainly to the contralateral brain hemispheres, with only little direct interhemispheric coupling. Thus, monocular occlusion has been frequently used in chicks to document functional specialization of the two hemispheres. However, we do not know whether monocular occlusion influences hippocampal activation. The aim of the present work was to fill this gap by directly testing this hypothesis. To induce hippocampal activation, chicks were exposed to a novel environment with their left or right eye occluded, or in conditions of binocular vision. Their hippocampal expression of c-Fos (neural activity marker) was compared to a baseline group that remained in a familiar environment. Interestingly, while the hippocampal activation in the two monocular groups was not different from the baseline, it was significantly higher in the binocular group exposed to the novel environment. This suggest that the representation of environmental novelty in the hippocampus of domestic chicks involves strong binocular integration.
在鸟类中，与哺乳动物一样，海马体对暴露于新环境特别敏感，这种功能基于视觉输入。雏鸡的眼睛位于侧面，其视神经纤维主要投射到对侧大脑半球，只有很少的直接半球间耦合。因此，单眼遮盖在雏鸡中经常被用来记录两个半球的功能专业化。然而，我们不知道单眼遮盖是否会影响海马体的激活。本研究的目的是通过直接测试这一假设来填补这一空白。为了诱导海马体的激活，雏鸡的左眼或右眼被遮盖，或者在双眼视觉的条件下，暴露于新环境中。将它们的海马体中 c-Fos（神经活动标志物）的表达与留在熟悉环境中的基线组进行比较。有趣的是，虽然两个单眼组的海马体激活与基线组没有差异，但在暴露于新环境的双眼组中，其激活显著更高。这表明，家鸡海马体对环境新奇性的表示涉及强烈的双眼整合。
