Design basics

Please see Rik Henson's excellent discussion of fMRI DesignEfficiency

MatthewBrett gave a talk at HBM2006 on avoiding errors in design and analysis. The text below is a slight expansion of the last few slides.

The importance of having an anatomical hypothesis

This is my (MatthewBrett) personal view for what it's worth.

An interesting imaging experiment has to go further than where brain activity is, and tell us something about what the brain activity means in terms of how the brain works
As a consequence, a brain imaging experiment without an anatomical hypothesis rarely tells us much about how the brain works
It is very rare for an experiment to have no anatomical hypothesis atall, but an experiment with a weak anatomical hypothesis asks a question like "where in the brain is activity for task T"
An strong anatomical hypothesis usually leads to a question like "what does activity in region R tell me about the contribution of R to the computations of task T"

Sketch your ideal of how the paper will turn out while you are designing the study
Draw a cartoon or your expected brain activation and brain activation if your hypothesis is not correct
Make sure that you know how to use the difference between the activations above to be able to test your hypothesis
The following may be signs that you have a weak anatomical hypothesis:
- "Neural correlates" in your title!
- Introduction that concentrates on the task much more than the brain
- Long list of activations in your discussion with lists of previous studies activating these areas