Central connections of the optic nerves in mammals with pure-cone retinae

✍ Scribed by Peter Johnston, J. ;Gardner, Ernest

• Publisher: John Wiley and Sons
• Year: 1959
• Tongue: English
• Weight: 643 KB
• Volume: 134
• Category: Article
• ISSN: 0003-276X
• DOI: 10.1002/ar.1091340207

✦ Synopsis

Some years ago Walls ('42) pointed out that mammals with pure-cone retinae apparently occur only in the family Sciuridae, and that in this family, grouncl squirrels arc tlie most strongly diuriial. In spite of the obvious advantages of using these animals for studies of vision, little experimental work has been done aiid there have been no ariatorriical studies of the central visual pathways.

Bornschein ('54), who appears to have been the first to study the electroretinogram of squirrels, published records obtained from the souslik (Citellzrs citellzrs). He pointed out that relatively intense illumination had to bc used. Previously, Karli ('51) had established that tlie retina of this animal is a pure-cone retina. The ratio of cones to ganglion cells was about 2:1, aiid in some areas of the retina was about 1: 1. Vilter ( '54) published similar findings on the same species, a i d contrasted the retina with that of the guinea pig. Arden and Tansley (%a, '5%) descrihed the spectral sensitivity of the pure-cone retina of the grey squirrel This investigation mas supported by research grant B-1201 from the Xationel