¥ In each voxel, fit data Zn to a curve of the form
¥ Zn È a + b×tn + b×rn for n=0,1,É,N-1 (N=# time pts)
¥ a, b,
b are unknown parameters to be calculated in each voxel
¥ a,b
are ÒnuisanceÓ baseline
parameters
¥ b is
amplitude of r(t ) in data
= Òhow
muchÓ
BOLD
¥ Baseline model might be more complicated
for long (> 200 s) continuous imaging
runs:
¥ T < 300 s: a+b×t+c×t 2
¥ Longer: a+b×t+c×t 2 + ŽT/200 low
frequency components
¥ Might also include as extra baseline
components the estimated subject head
movement time series, in order to remove
residual contamination from such artifacts