Fig 5: Impact of 3rd order shim-induced Fuzzy Ripples on fMRI activation detectability.

This figure demonstrates how Fuzzy Ripples, induced by the 3rd order shim, can affect the detectability of fMRI activation. These data refer to 2D-EPI with block designed auditory activation with NORDIC denoising. When the 3rd order shim is connected, the Fuzzy Ripples can be so pronounced that they mask parts of the auditory activation, preventing it from reaching the detection threshold. White arrows indicate areas where the Fuzzy Ripples are more intense with the 3rd order shim engaged. Although Fuzzy Ripples are still present when the 3rd order shim is disconnected, they are less severe. Acquisition parameters of data presented here are mentioned in methods section 3.4. See Supplementary Fig. S2 for a replication of these findings in a different participant.