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Dissertation_PaulBonezzi_2020.pdf (13.97 MB)

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The development of outer retinal photoresponsivity and the effects of sensory deprivation

Bonezzi, Paul J
http://rave.ohiolink.edu/etdc/view?acc_num=akron1602525875711526

Abstract Details

2020, Doctor of Philosophy, University of Akron, Integrated Bioscience.
Visual processing begins with phototransduction when rod and cone photoreceptors in the outer retina transform incident photons into electrochemical potentials. The unique spectral sensitives of the expressed light-sensitive opsin (s) as well as several other factors shape an individual photoreceptors response properties. Subsequently, photoreceptor outputs distribute amongst distinct postsynaptic partners establishing parallel intraretinal channels for information flow. Furthermore, light-evoked responses in the mouse retina are known to increase significantly after eye-opening between postnatal days 12-14 (P12-14). This correlates with activities of the inner retina, confirming that outer retinal function increases after eye-opening and stabilizes around P30 (maturity). Previous in-vivo electroretinogram (ERG) studies have demonstrated light-evoked photoreceptor activity at P10. Such responses coincide with initial synaptogenesis between photoreceptors and second-order bipolar cells. However, this is a full 2-3 days after synaptogenesis of bipolar cells and third-order ganglion cells that relay retinal outputs to higher-order visual system regions. Moreover, various developmental factors determine the onset of photoreceptor responsivity, one being the gradual increase in phototransduction-specific genes and proteins. In partial disagreement with previous electrophysiological findings, molecular analyses indicate that much of the machinery for cone phototransduction is present before P10 and just before eye-opening in rods. Therefore, it was hypothesized that photoreceptors are responsive and second-order bipolar cells can respond to photoreceptor output days before eye-opening in mice. It was found that photoreceptor-evoked a-waves were detected in response to both green and UV flashes of light at P8 and bipolar cell-evoked b-waves were responsive within the 24 hours to follow using ex-vivo electroretinograms (ERGs). Furthermore, seminal studies have demonstrated that during critical developmental time points, light-evoked activity contributes, in a myriad of ways, to the refinement of higher-order circuits of the visual system. However, few studies have explored the effects of sensory deprivation on photoreceptors and their respective second-order responses. Therefore, it was of interest to determine the role of early sensory experience on the functionality of such retinal circuits. It was determined that deprivation alters both the photoreceptor response properties as well as the second-order responses of ON-bipolar cell responses, but in unique ways.
Jordan Renna (Advisor)
Qin Liu (Committee Member)
Adam Smith (Committee Member)
Merri Rosen (Committee Member)
Yong Lu (Committee Member)
204 p.
Biology; Biophysics; Cellular Biology; Evolution and Development; Molecular Biology; Neurobiology; Neurosciences; Optics; Physiology
retina; photoreceptors; development; rods; cones; retinal processing; mouse; electroretinogram; bipolar cells; sensory deprivation; visual system; phototransduction; electrophysiology

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Citations

  • Bonezzi, P. J. (2020). The development of outer retinal photoresponsivity and the effects of sensory deprivation [Doctoral dissertation, University of Akron]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=akron1602525875711526

    APA Style (7th edition)

  • Bonezzi, Paul. The development of outer retinal photoresponsivity and the effects of sensory deprivation. 2020. University of Akron, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=akron1602525875711526.

    MLA Style (8th edition)

  • Bonezzi, Paul. "The development of outer retinal photoresponsivity and the effects of sensory deprivation." Doctoral dissertation, University of Akron, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=akron1602525875711526

    Chicago Manual of Style (17th edition)

akron1602525875711526
280
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This open access ETD is published by University of Akron and OhioLINK.