|title||Design and Analysis of fMRI Experiments Probing Brain Activity Induced by Tactile Stimulation|
This thesis presents the design and analysis of fMRI experiments on the processing of tactile information in the human brain. For this purpose the principles of neurology and fMRI relevant for the experiments are introduced. A pneumatically driven tactile display, whose non-interference with the fMRI image acquisition is verified, is used to effect tactile stimulation. The somatotopic representations in the primary and the secondary somatosensory cortex are successfully mapped at two distinct points (index finger and foot) for three healthy, seeing subjects. The analysis is performed by means of statistical parametric mapping of t-scores, a hypothesis testing approach based on the general linear model. The tactile stimulations elicited activation of the primary motor cortex for almost all image series in spite of precautions with regard to the subjects"comfort and immobility. The reproducibility of the resulting brain activities is examined in terms of location, extent and significance. It turns out that the location of the most significant point of activity can be reliably reproduced using three dimensional maps of t-scores while extent and intensity are subject to large random variations.