眼视-视网膜离心系统,中枢神经系统的恒定组成部分,似乎存在于所有脊椎动物群体中,是终末神经(TN)复合体的一部分。TN允许整合不同的感官模式,其解剖变异性可能具有功能和进化意义。我们建议TN的视网膜分支是重要的解剖学联系,可以在Austrolebias中实现嗅觉和视觉系统之间的功能相互作用。通过注射三种不同的神经元示踪剂(生物细胞素,辣根过氧化物酶,和1,1\'-双十八烷基-3,3\',Austrolebiascharrua鱼类左眼的3\'四甲基-吲哚花青高氯酸盐(DiI)),我们确定了TN的眼视视网膜分支和相关的神经元体,它们可以通过位置区分,形状,和大小。耳部视网膜TN分支由许多细轴突组成,这些轴突沿嗅球(OB)和端脑叶向腹侧延伸,并且似乎起源于一组位于同侧和对侧OB(称为区域1)的延髓部分的许多小单极神经元。在另外两个区域中发现了标记的细胞:OB和端脑叶之间过渡的双极和多极神经元(区域2),以及视前/前盖区的另外两个组(区域3)。在这最后一个地区,最前端的群由单极梨形神经元组成,可能属于视前隔TN复合体。第二组,假定位于前科区域,由假单极神经元形成,与不参与TN复合物的离心视网膜系统的保守脊椎动物核一致。发现嗅觉和视觉系统之间的连接通过眼图-视网膜TN分支表明这些感觉模式之间的早期相互作用,并有助于确定他们目前未知的电路组织。
The olfacto-retinal centrifugal system, a constant component of the central nervous system that appears to exist in all vertebrate groups, is part of the terminal nerve (TN) complex. TN allows the integration of different sensory modalities, and its anatomic variability may have functional and evolutionary significance. We propose that the olfacto-retinal branch of TN is an important anatomical link that allows the functional interaction between olfactory and visual systems in Austrolebias. By injecting three different neuronal tracers (biocytin, horseradish peroxidase, and 1,1\'-dioctadecyl-3,3,3\',3\'tetramethyl-indocarbocyanine perchlorate (DiI)) in the left eye of Austrolebias charrua fishes, we identified the olfacto-retinal branch of TN and related neuronal somas that were differentiable by location, shape, and size. The olfacto-retinal TN branch is composed of numerous thin axons that run ventrally along the olfactory bulb (OB) and telencephalic lobes, and appears to originate from a group of many small monopolar neurons located in the rostral portion of both the ipsi- and contralateral OB (referred to as region 1). Labeled cells were found in two other regions: bipolar and multipolar neurons in the transition between the OB and telencephalic lobes (region 2) and two other groups in the preoptic/pretectal area (region 3). In this last region, the most rostral group is constituted by monopolar pear-shaped neurons and may belong to the septo-preoptic TN complex. The second group, putatively located in the pretectal region, is formed by pseudounipolar neurons and coincides with a conserved vertebrate nucleus of the centrifugal retinal system not involved in the TN complex. The found that connections between the olfactory and visual systems via the olfacto-retinal TN branch suggest an early interaction between these sensory modalities, and contribute to the identification of their currently unknown circuital organization.