Generic brain activation mapping in functional magnetic resonance imaging: a nonparametric approach.
We report a novel method to identify brain regions generically activated by periodic experimental design in functional magnetic resonance imaging data. This involves: 1) registering each of N individual functional magnetic resonance imaging datasets in a standard space; 2) computing the median standardised power of response to the experimental design; 3) testing median standardised power at each voxel against its nonparametrically ascertained distribution under the null hypothesis of no experimental effect; and 4) constructing a generic brain activation map. The method is validated by analysis of 6 null images, acquired under conditions when the null hypothesis was known to be true; 8 images acquired during periodic auditory-verbal stimulation; and 6 images acquired during periodic performance of a covert verbal fluency task.
Brammer
M J
MJ
Department of Biostatistics, Institute of Psychiatry, London. m.brammer@iop.bpmf.ac.uk
Bullmore
E T
ET
Simmons
A
A
Williams
S C
SC
Grasby
P M
PM
Howard
R J
RJ
Woodruff
P W
PW
Rabe-Hesketh
S
S
D000161:Acoustic Stimulation; D001303:Auditory Cortex / Q000502:physiology; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D012815:Signal Processing, Computer-Assisted