Investigation of alternating and continuous experimental task designs during single finger opposition fMRI: A comparative study

The purpose of this study was to empirically investigate and compare the ef fects of alternating and continuous experimental task designs on blood oxyg enation level dependent (BOLD) signal contrast. Six healthy volunteers unde rwent single-finger opposition functional magnetic resonance imaging (fMRI) using T2*-weighted echo planar imaging technique on a 1.5 T MR scanner. Tw o different acquisition patterns were tested: alternating (ABABAB) and cont inuous (AAABBB), rest: A, activation: B. The BOLD signal contrast within a primary motor cortex region of interest (ROI) was evaluated using normalize d t-values (z-scores) and mean region of interest (ROI) intensity for the t wo patterns. Analysis of variance (ANOVA) on ROI mean z-score and signal in tensities demonstrate that the alternating pattern of administering rest an d activation epochs produced a more robust statistical difference than a co ntinuous pattern. The results showed that different patterns of acquisition yield differences in the BOLD signal at field strength of 1.5 T, and that an alternating task design can be considered more optimal than a continuous task design.