The file "Localizing_epileptic_activity_dataset" has one row per observation time (every 
0.28 seconds).  The left-most column is the observation time.  The next 12 columns give 
measurements of each of 12 regions in the brain (reg1, reg2, etc.).  Each region's 
measurement at a time is the percent change in the average pixel value of that region at 
that time relative to the average pixel value at time 0, for light of wavelength 535 nm. 

The data analyzed in the book is from Region 1 (reg1).  The other regions do different 
interesting things.