fMRI Methods & Data Analysis

fMRI Methods & Data Analysis

1. How does MRI measure brain function?

   • Introduction to MRI
     • Structural imaging
       • Brain anatomy
       • 3D image of brain
     • Functional imaging
       • Brain function
       • Slices, Volumes and slice thickness
       • Voxels
   • The BOLD signal
     • From voxels
     • Neural activity -> blood flow -> oxyhaemoglobin -> MR signal

2. fMRI analytical techniques

   • Task-related fMRI
     • Analyse changes in BOLD signal
     • Voxels exhibit an HRF
     • Analysis at single subject and group level
     • Interpretation
       • Correlational appraoch
       • Networks and connectivity
       • How the region is activated?
       • Forward and reverse inference
     • Neurobollocks case study
       • Your Brain on Politics
       • Logical fallacy
   • fMRI Designs: Blocked
     • Shows participants stimuli in blocks followed by rest blocks
     • Advantages
       • High detection power
       • The most widely used approach for fMRI studies
     • Disadvantages
       • Subjects get into mental set for block
       • Very predictable for subjects
       • Can't look at effects of single events
   • fMRI Designs: Event-Related
     • A single trial at a time as opposed to blocks
     • Advantages
       • Complex desgin, random task presentation
       • Can create post-hoc conditions
     • Disadvantages
       • Reduced power
       • Accurate detection rates require accurate HRF modelling

3. How do we "preprocess" fMRI data?

   • Motion correction of functional images
   • Slice timing correction of functional images
   • Normalisation of anatomical and functional images
   • Smoothing