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dc.contributor.advisorStell, William
dc.contributor.advisorSauve, Yves
dc.contributor.advisorBaldridge, William
dc.contributor.authorShi, Qing
dc.date.accessioned2014-07-17T20:17:59Z
dc.date.available2014-11-17T08:00:38Z
dc.date.issued2014-07-17
dc.date.submitted2014en
dc.identifier.citationShi, Q. (2014). Mechanisms of Adaptation to Mean Light Intensity in the Chick Retina (Unpublished doctoral thesis). University of Calgary, Calgary, AB. doi:10.11575/PRISM/26863en_US
dc.identifier.urihttp://hdl.handle.net/11023/1637
dc.description.abstractThrough adaptation, animals can function visually under an enormous range of light intensities. Adaptation to changes in light intensity takes place early, in the retina. One role of adaptation is to regulate the spatiotemporal tuning of retinal outputs via retinal ganglion cells. In my project, I used the optokinetic response (OKR) to characterize contrast sensitivity (CS) in the chick retina as a function of spatial frequency and temporal frequency at different mean light intensities. I first found that adaptation from light to dark caused a shift in tuning preference of CS (Chapter 2). In the daytime, photopic CS of the chick was tuned to spatial frequency; whereas in the nighttime, scotopic CS was tuned to temporal frequency. Later, I explored mechanisms that modulated spatiotemporal CS under different adaptational conditions (Chapter 3). Since dopamine (DA) and nitric oxide (NO) are putative light-adaptation messengers in the retina, I injected agents affecting DA and NO actions and gap junction coupling into the eyes (vitreous bodies) of dark- or light-adapted chicks. Finally, I investigated the role of cell-cell coupling, a downstream mediator of DA or NO actions in the retina, in adaptation. I demonstrated that the chick uses a similar strategy to that used by mammals, to adapt to ambient illumination; and that DA, NO, as well as cell-cell coupling are adaptation-sensitive modulators of spatiotemporal visual processing in the retina. Optokinetic CS is a rapid and noninvasive method for assessing retinal function, which can be manipulated rapidly, conditionally and reversibly by intravitreal injection of specific pharmacological agents. The chick’s large eyes, and the similarities of control of light adaptation in chick and other species (e. g., mouse), make the chick a powerful new model for retinal research.en_US
dc.language.isoeng
dc.rightsUniversity of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.
dc.subjectNeuroscience
dc.subject.classificationretinaen_US
dc.subject.classificationAdaptationen_US
dc.subject.classificationoptokinetic responseen_US
dc.subject.classificationDopamineen_US
dc.subject.classificationnitric oxideen_US
dc.subject.classificationcell-cell couplingen_US
dc.titleMechanisms of Adaptation to Mean Light Intensity in the Chick Retina
dc.typedoctoral thesis
dc.publisher.facultyGraduate Studies
dc.publisher.institutionUniversity of Calgaryen
dc.identifier.doihttp://dx.doi.org/10.11575/PRISM/26863
thesis.degree.nameDoctor of Philosophy
thesis.degree.namePhD
thesis.degree.disciplineNeuroscience
thesis.degree.grantorUniversity of Calgary
atmire.migration.oldid2338
dc.publisher.placeCalgaryen
ucalgary.item.requestcopytrue


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University of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.