UBC Theses and Dissertations
A study of the human visual evoked potential Bennett, John Reavely
A new approach to the study of the human Visual Evoked Potential is described, based on a simple model of the visual system. This model is then used as a tool for the investigation of the visual system and its characteristics. Certain assumptions are made concerning the spontaneous brain activity accompanying the visual response and this activity is then described by its probability density and auto-correlation functions. A theoretical basis is described for the two noise reduction techniques of ensemble averaging and the sliding mean and the implications of these processing procedures as applied to the visual system are discussed with reference to the system model. The theoretical assumptions of this analysis are then experimentally investigated. The nature of the visual response is discussed and it is shown that this response can be subdivided into two components on the basis of their time behaviour. Each of these two components, the V.E.P. and the Rhythmic After-discharge is investigated in detail. The relation of the Alpha Rhythm to the After-discharge is also investigated using auto-correlation techniques. Finally, a statistical model for the V.E.P. is described as a means for studying and applying the visual response, its uses, being discussed in some detail. An electronic coding scheme was designed to facilitate the cataloguing of experimental data, and is described in the Appendix.
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