I decided I should standardize my fMRI data across sessions by rescaling each voxel to have a run-mean of 100. Normalized data looked okay under manual inspection in FreeView. When I tried to analyze this data, however, I consistently get an error partway through:

"""
Index exceeds matrix dimensions.

Error in fast_selxavg3 (line 762)
      acfrun = nrho1segmn(nthseg).^([0:flac.ntp-1]');
 
>> ------------------------------------------
ERROR: fast_selxavg3() failed\n
a_100_Av_s_task_fmov_bgrnd failed
"""