INTERPRETING THE RESULTS OF MELODIC
1. Melodic identifies groups of voxels that are temporally correlated.
2. These are called Components
3. The Output of Melodic displays these various components
Note: The following Picture shows a particular component identified by Melodic
The following Graph charts the timecourse of the component identified by Melodic
The following Graph charts the "Fourier Transform" of the timecourse that was previously identified by Melodic
The task of the researcher is to examine the spatial distribution and/or timecourse of each component to determine whether it is meaningful to the data analysis.
FOR EXAMPLE: Based on the spatial distribution of the component around the edges of the brain, the following Melodic Report, suggests that this component is possibly motion artifact..
The numbers on the Y axis represent the change of voxel intensity compared to baseline....the X axis represents the time line increments.
Generally speaking, if the activation occurs around the edge of the brain or around the ventricles, it is reasonable to presume that it could be motion artefact because any small motion at a border can result in large fluctuations in intensity.