Microsaccades

The first thing we do upon waking is open our eyes. Rotating them in our eye sockets, we scan our surroundings and collect the information into a picture in our head. Eye movements can be split into saccades and fixational eye movements, which occur when we attempt to fixate our gaze. The latter consists of microsaccades, drift and tremor. Before we even lift our eye lids, eye movements – such as saccades and microsaccades that let the eyes jump from one to another position – have partially been prepared in the brain stem. Saccades and microsaccades are often assumed to be generated by the same mechanisms. But how saccades and microsaccades can be classified according to shape has not yet been reported in a statistical manner. Research has put more effort into the investigations of microsaccades’ properties and generation only since the last decade. Consequently, we are only beginning to understand the dynamic processes governing microsaccadic eye movements. Within this thesis, the dynamics governing the generation of microsaccades is assessed and the development of a model for the underlying processes. Eye movement trajectories from different experiments are used, recorded with a video-based eye tracking technique, and a novel method is proposed for the scale-invariant detection of saccades (events of large amplitude) and microsaccades (events of small amplitude). Using a time-frequency approach, the method is examined with different experiments and validated against simulated data. A shape model is suggested that allows for a simple estimation of saccade- and microsaccade related properties. For sequences of microsaccades, in this thesis a time-dynamic Markov model is proposed, with a memory horizon that changes over time and which can best describe sequences of microsaccades.

Level thesis:degree_level

thesis.doctoral

Grantor dc:publisher

Universität Potsdam

Year

2012

Author dc:creator

• Bettenbühl, Mario

Contributors dc:contributor

• Holschneider, Matthias

• Mikrosakkaden
• Fixationsbewegungen der Augen
• Sakkadendetektion
• Mikrosakkadensequenzen
• Waveletanalyse
• microsaccades
• fixational eye movements
• saccade detection
• sequences of microsaccades
• wavelet analysis

Statement dc:rights

• CC-BY - Namensnennung 4.0 International

Repository record source_url

https://publishup.uni-potsdam.de/frontdoor/index/index/docId/7030

OAI identifier oai:identifier

oai:kobv.de-opus4-uni-potsdam:7030