Optimization of proprioceptive stimulation for echo-planar and inverse magnetic resonance imaging

Abstract

In echo-planar imaging (EPI), the optimal passive movement parameters (rate and duration) for studying proprioceptive brain responses are unknown. The aim of this thesis was to test the effect of stimulus rate on brain responses evoked by proprioceptive stimulation in EPI. In addition, we attempted to develop a measurement protocol for experiments focused on proprioception in ultrafast inverse magnetic resonance imaging (InI) and investigate the amplitude of blood oxygen level-dependent (BOLD) signal at varying stimulus duration. This experimental setup was supposed to be applied in future connectivity studies of the proprioceptive brain network. We found that the optimum rate for right index finger proprioceptive stimulation in EPI varies from 3 to 6 Hz. While we managed to sample the BOLD responses every 100 ms (a 20-fold increase in temporal resolution compared to EPI), the experimental design in InI is challenging due to methodological constraints. Thus, the appropriate stimulation parameters for InI still remain a topic for further research.