Temporal Changes of BOLD FMRI Activation in a Block Design

Arthur Peter Wunderlich¹, Gregor Stuber¹, Wolfgang Freund¹

To study the temporal variability of the BOLD response, we investigated 15 healthy subjects while stimulating their index finger electrically for 52 s. Activation was repeated six times followed by rest for 26 s. Additional data were acquired starting 26 s before the first stimulation. In SPM analysis, we modelled the paradigm, activation and following rest, as one regressor per acquired volume. As reference (off-condition), the resting phase before the first stimulation was chosen. The group analysis shows a slow spatial change of activation maxima during continuous stimulation and activation lasting as long as 20 s after the end of stimulation.