Assessing visual requirements for social context-dependent activation of the songbird song system
Assessing visual requirements for social context-dependent activation of the songbird song system
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DOI：
10.1098/rspb.2008.1138
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发表时间：
2009-01-22
影响因子：
4.7
通讯作者：
Jarvis, Erich D.
中科院分区：
文献类型：
--
作者：
Hara, Erina;Kubikova, Lubica;Jarvis, Erich D.
社会背景已经被证明对广泛的脊椎动物物种的大脑激活有深远的影响。在鸣禽中最好的研究是，当雄鸟唱非定向歌曲时，几个歌核中的神经活动和即刻早期基因(IEGs)的表达水平显著高于或低于它们对其他鸟类，特别是雌性鸟类唱歌时的水平。这种不同的社会语境依赖的激活独立于听觉输入，并不简单地依赖于歌唱的运动动作。这些发现表明，驱动大脑中社会背景相关差异的关键感觉通道可能是视觉线索。在这里，我们通过检测视觉输入正常或受阻的大脑半球歌核的IEG激活来检验这一假设。我们发现，遮盖一只眼睛在视觉上阻止了IEG在大脑的两个对侧视觉通路中的表达，并减少了对侧腹侧被盖区的激活，腹侧被盖区是受社会背景影响的非视觉中脑动机相关区域。然而，阻断视觉输入对女性定向歌唱时对侧歌唱核团的社会语境依赖性激活没有影响。我们的研究结果表明，个体感觉通道并不是歌唱过程中歌曲核团社会语境差异的直接驱动力。相反，大脑激活的这些社会背景差异似乎更多地依赖于另一个人在场的一般意义上。
Social context has been shown to have a profound influence on brain activation in a wide range of vertebrate species. Best studied in songbirds, when males sing undirected song, the level of neural activity and expression of immediate early genes (IEGs) in several song nuclei is dramatically higher or lower than when they sing directed song to other birds, particularly females. This differential social context-dependent activation is independent of auditory input and is not simply dependent on the motor act of singing. These findings suggested that the critical sensory modality driving social context-dependent differences in the brain could be visual cues. Here, we tested this hypothesis by examining IEG activation in song nuclei in hemispheres to which visual input was normal or blocked. We found that covering one eye blocked visually induced IEG expression throughout both contralateral visual pathways of the brain, and reduced activation of the contralateral ventral tegmental area, a non-visual midbrain motivation-related area affected by social context. However, blocking visual input had no effect on the social context-dependent activation of the contralateral song nuclei during female-directed singing. Our findings suggest that individual sensory modalities are not direct driving forces for the social context differences in song nuclei during singing. Rather, these social context differences in brain activation appear to depend more on the general sense that another individual is present.