i Acknowledgements ii List of publications/conference proceedings iii 1. General Introduction 1 1.1. Factors contributing to elderly falls 1 1.1.1. Age-related changes in gait characteristics 2 1.1.2. Neuromuscular function 3 1.1.3. Summary 6 1.2. Changes in the acquisition of sensory information 6 1.2.1. Somatosensory information 6 1.2.2. Vestibular function 8 1.2.3. Head stabilisation 10 1.2....

A sequence for the fast acquisition of T1 weighted structural brain images with whole brain coverage and isotropic resolution of 1mm is presented. It is based on MDEFT with a FLASH-EPI hybrid readout. Several techniques for artefact suppression are implemented, like echo time shifting, asymmetric k-space sampling, and navigator echo acquisition. It is shown experimentally that the hybrid MDEFT ...

Many insects actively explore their near-range environment with their antennae. Stick insects (Carausius morosus) rhythmically move their antennae during walking and respond to antennal touch by repetitive tactile sampling of the object. Despite its relevance for spatial orientation, neither the spatial sampling patterns nor the kinematics of antennation behavior in insects are understood. Here...

In geostatistics, spatial data will be analysed that often come from irregularly distributed sampling locations. Interest is in modelling the data, i.e. estimating distributional parameters, and then to predict the phenomenon under study at unobserved sites within the corresponding sampling domain. The method of universal kriging for spatial prediction was introduced to cover the problem of spa...

The superior vena cava syndrome is due to the increased venous pressure in the upper torso, neck and head, caused by the obstruction of the superior vena cava. Both external and internal factors cause obstruction (95% are malign causes), and the most severe manifestation is represented by cerebral edema that can even lead to coma. The diagnostic algorithm for the superior vena cava syndrome is ...

In geostatistics, spatial data will be analysed that often come from irregularly distributed sampling locations. Interest is in modelling the data, i.e. estimating distributional parameters, and then to predict the phenomenon under study at unobserved sites within the corresponding sampling domain. The method of universal kriging for spatial prediction was introduced to cover the problem of spa...

A study is reported of target acquisition in 3D using a head coupled stereo display and a hand tracking device. The effects of lag and frame rate were studied by introducing lag in three different ways: by queuing the hand input and delivering it to the cursor an integer number of frames later, by increasing the frame interval and sampling the input device at the start of the display interval, ...

Three-dimensional gradient echo (GRE) is the main workhorse sequence used for susceptibility weighted imaging (SWI), quantitative susceptibility mapping (QSM), and susceptibility tensor imaging (STI). Achieving optimal phase signal-to-noise ratio requires late echo times, thus necessitating a long repetition time (TR). Combined with the large encoding burden of whole-brain coverage with high re...

The direction of social attention from groups provides stronger cueing than from an individual. It has previously been shown that both basic visual features such as size or orientation and more complex features such as face emotion and identity can be averaged across multiple elements. Here we used an equivalent noise procedure to compare observers' ability to average social cues with their ave...