Simultaneous Measurement of Signal Fluctuations in GE and SE BOLD Data During Resting State FMRI at 7T

Jack Harmer¹, Richard Bowtell¹, Susan Francis¹

Spontaneous, low frequency fluctuations in connected networks have been identified in T2*-weighted gradient-echo (GE) BOLD data. Here, we use a dual GE-SE-EPI sequence at 7T to identify functional connectivity maps in SE and GE BOLD data using ICA analysis. We assess the correlation of signal fluctuations in the SE and GE time-series, showing a higher correlation in the DMN than in global grey matter. We calculate the ratio of the changes in relaxation rates underlying the signal fluctuations, δR2*/δR2, to be 1.910.30 in grey matter, in good agreement with the value of ~2.1 found for task-induced changes in motor cortex.