首页   按字顺浏览 期刊浏览 卷期浏览 The Visual System of the Florida Garfish,Lepisosteus platyrhincus(Ginglymodi)
The Visual System of the Florida Garfish,Lepisosteus platyrhincus(Ginglymodi)

 

作者: Shaun P. Collin,   R. Glenn Northcutt,  

 

期刊: Brain, Behavior and Evolution  (Karger Available online 1993)
卷期: Volume 42, issue 6  

页码: 295-320

 

ISSN:0006-8977

 

年代: 1993

 

DOI:10.1159/000114168

 

出版商: S. Karger AG

 

关键词: Retinal ganglion cells;Topography;Horizontal streak;Dendritic field;Biplexiform cell;Vision;Vitreal vascularization;Holostei;Fishes

 

数据来源: Karger

 

摘要:

The vitreal vascularization, optic nerve fiber layer and the retinal ganglion cells are examined in the Florida garfish, one of the two surviving genera of the ginglymode group of actinopterygian fishes. In the absence of a choroidal gland, a well developed system of hyaloid blood vessels overlie the inner retina. The optic nerve fiber and ganglion cell layers are integrated to form a series of alternating columns or fascicles emanating from an elongated optic nerve head. Horseradish peroxidase or cobaltous lysine infusion from the optic nerve reveals seven ganglion cell classes based on soma size and position, dendritic field size, retinal coverage and terminal stratification. Two discrete populations of giant ganglion cells with large somata and large dendritic fields stratify either within the sclerad region (type I cells) and/or within the middle region (type 2 cells) of the inner plexiform layer. Both giant ganglion cell populations (1% of total) form evenly distributed arrays with the dendritic arbor of each type covering the retina completely. Between seven and nine type 2 cells overlap the dendritic field of a single type 1 cell. Type 3 cells are small and located in the inner nuclear layer with a multistratified dendritic field terminating throughout the inner plexiform layer. Topographic analysis of the population of type 3 cells (4% of total) reveals a temporal area centralis (6.25 × 102 cells per mm2) and a ventral horizontal streak (6.25 × 102 cells per mm2). The large population of cells within the ganglion cell layer are classified as types 4, 5 and 6 based on soma size, dendritic field size and dendritic stratification and collectively these cells match the distribution of ganglion cells within the inner nuclear layer with 5.3 × 103 cells per mm2 in the temporal area centralis and 8.6 × 103 cells per mm2 in the horizontal streak. Type 7 cells possess small somata and send branches into both the inner and outer plexiform layers and have been termed biplexiform ganglion cells. Phylogenetic comparisons of several morphological features of the garfish retina reveals the polarity, conservation and the evolution of a number of visual characters.

 

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