![Echo planar magnetic resonance images (fMRI)](https://webarchive.library.unt.edu/eot2008/20090130210741im_/http://www.niaaa.nih.gov/NR/rdonlyres/EEC274D8-C2C7-42D2-BDA8-82544AA70B74/0/echoPlanar_med.jpg)
(a) average of fMRI time series.
(b) sample SD of on/off block difference images.
(c) sample average of on/off block differences.
(d) wavlet coefficients of (c) for 4-level transform.
(e) significant (alpha = 0.05) wavelet coefficients.
(f) inverse wavlet transform of (e) yields estimate of activation signal.
This illustration is from NIAAA's Laboratory of Clinical Studies, Section of Brain Electrophysiology and Imaging
Updated: August 2002