This study employed adaptation paradigms to explore visual motion processing during smooth pursuit eye movement. Two classes of model, classical models and reference signal models, employ estimates of retinal motion and pursuit to estimate head-centred world motion. The pursuit estimate in classical models is purely extra-retinal. In reference signal models the pursuit estimate is additionally modulated by retinal feedback. Chapters 2 and 3 investigated the motion aftereffect (MAE) following adaptation to simultaneous retinal motion and smooth pursuit. In chapter 2 adaptations to either horizontal retinal motion or vertical smooth pursuit respectively resulted in retinal or extra-retinal MAE. Simultaneous orthogonal adaptation to both motions resulted in a unidirectional MAE that bisected the individual MAE directions. Adaptation to a head-centred motion signal (perceived direction) was not supported by the recorded directions for adapting motion and resulting MAE. An explanation employing separate lower level adaptations was favoured. Chapters 3 and 4 examined motion perception following collinear motion adaptation. Additionally, the retinotopic nature of retinal motion adaptation was exploited to limit the effects of retinal sensor adaptation during the test phase. The two classes of model then make differing predictions: Reference signal models predict a pursuit estimate that is modulated by retinal motion, whilst classical models do not. In chapter 3 varying the background motion during adaptation did alter the physical eye movement. However, the properties of the resulting MAE were not modulated by retinal feedback and a classical model was supported. Chapter 4 used a moving test to quantify the perceived stability of a background during smooth pursuit using a two alternative forced choice paradigm and staircase procedure. Either a phantom velocity aftereffect or a modified reference signal model was suggested as modulating the Filehne illusion in Experiment 6. Two control experiments failed to find evidence for phantom adaptation. Experiment 9 demonstrated a potential retinotopic location bias for background motion when applying a reference signal model, background motion above the test area did not alter perceived stability judgments.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:584917 |
| Date | January 2010 |
| Creators | Davies, Jonathan Rhys |
| Publisher | Cardiff University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://orca.cf.ac.uk/54529/ |
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