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

J Comput Assist Tomogr. 2000 Nov-Dec;24(6):935-41. doi: 10.1097/00004728-200011000-00021.

Abstract

The purpose of this study was to empirically investigate and compare the effects of alternating and continuous experimental task designs on blood oxygenation level dependent (BOLD) signal contrast. Six healthy volunteers underwent single-finger opposition functional magnetic resonance imaging (fMRI) using T2*-weighted echo planar imaging technique on a 1.5 T MR scanner. Two different acquisition patterns were tested: alternating (ABABAB) and continuous (AAABBB), rest: A, activation: B. The BOLD signal contrast within a primary motor cortex region of interest (ROI) was evaluated using normalized t-values (z-scores) and mean region of interest (ROI) intensity for the two patterns. Analysis of variance (ANOVA) on ROI mean z-score and signal intensities demonstrate that the alternating pattern of administering rest and activation epochs produced a more robust statistical difference than a continuous 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.

Publication types

  • Comparative Study

MeSH terms

  • Adolescent
  • Adult
  • Analysis of Variance
  • Artifacts
  • Brain / metabolism
  • Brain / physiology
  • Contrast Media
  • Echo-Planar Imaging
  • Fingers / physiology*
  • Humans
  • Image Enhancement / methods
  • Image Processing, Computer-Assisted / methods
  • Magnetic Resonance Imaging* / methods
  • Motor Cortex / metabolism
  • Motor Cortex / physiology
  • Motor Skills / physiology*
  • Oxygen / blood
  • Statistics, Nonparametric
  • Task Performance and Analysis*

Substances

  • Contrast Media
  • Oxygen