Spectral Sensitivity of the Goldfish ERG and Optic Tectum Before and After Optic Nerve Damage

• Main Author: Pile, Jenel
• Format: Others
• Published: TopSCHOLAR® 2001
• Subjects: Psychology
• Online Access: http://digitalcommons.wku.edu/theses/693; http://digitalcommons.wku.edu/cgi/viewcontent.cgi?article=1696&context=theses

It is well known that visual neurons in lower vertebrates regenerate after damage. Thus, the visual system has served as a useful model for neural regeneration studies. However, most of the research on neural regeneration has focused on the recovery of anatomical connections; little has been done assessing the return of visual function. The purpose of this study was to determine the return of function of the goldfish optic nerve at four time intervals after damage (crush). An increment threshold procedure was used to obtain electroretinogram (ERG) and tectal responses to light onset and termination to various wavelengths of light. Spectral sensitivity functions were derived from both the ON- and OFF-components at both visual levels. By examining the spectral sensitivity functions of these responses, it was possible to determine if there were differences in shape and absolute sensitivity among the ON- and OFF-responses at each wavelength within each level, as well as between the visual levels. The results of this study found that there are differences in the cone contributions between the ON-and OFF-components at both the ERG and tectal level of normal adult goldfish. Tectal responses from optic nerve crush subjects returned at approximately 41- days postcrush (dpc). In conclusion, the results of the present study show that the optic nerve re-establishes functional properties within the tectum after approximately 60-dpc.