Department of Computational Neuroethology, Max Planck Institute for Neurobiology of Behavior-caesar, Bonn, Germany.
Electron Microscopy and Analytics, Max Planck Institute for Neurobiology of Behavior-caesar, Bonn, Germany.
Commun Biol. 2024 Aug 14;7(1):992. doi: 10.1038/s42003-024-06697-2.
In most avian retinas, double cones (consisting of a principal and accessory member) outnumber other photoreceptor types and have been associated with various functions, such as encoding luminance, sensing polarized light, and magnetoreception. However, their down-stream circuitry is poorly understood, particularly across bird species. Analysing species differences is important to understand changes in circuitry driven by ecological adaptations. We compare the ultrastructure of double cones and their postsynaptic bipolar cells between a night-migratory European robin and non-migratory chicken. We discover four previously unidentified bipolar cell types in the European robin retina, including midget-like bipolar cells mainly connected to one principal member. A downstream ganglion cell reveals a complete midget-like circuit similar to a circuit in the peripheral primate retina. Additionally, we identify a selective circuit transmitting information from a specific subset of accessory members. Our data highlight species-specific differences in double cone to bipolar cell connectivity, potentially reflecting ecological adaptations.
在大多数禽类的视网膜中，双锥形细胞（由一个主锥形细胞和一个副锥形细胞组成）的数量多于其他光感受器类型，并且与各种功能有关，例如编码亮度、感应偏振光和磁受体。然而，它们的下游电路仍知之甚少，特别是在不同鸟类之间。分析物种差异对于理解由生态适应驱动的电路变化很重要。我们比较了夜间迁徙的欧洲知更鸟和非迁徙的鸡的双锥形细胞及其突触后双极细胞的超微结构。我们在欧洲知更鸟的视网膜中发现了四种以前未被识别的双极细胞类型，包括主要与一个主锥形细胞相连的小型双极细胞。一个下游的神经节细胞揭示了一个完整的类似于周边灵长类视网膜中的小型电路。此外，我们还确定了一个选择性的电路，该电路从特定的副锥形细胞亚群传递信息。我们的数据突出了双锥形细胞与双极细胞连接的物种特异性差异，这可能反映了生态适应。
