Ð16Ð
Linearity of HRF
¥ Multiple activation cycles in a voxel, closer in time than duration of HRF:
H Assume that overlapping responses add
H
¥ Linearity is a pretty good assumption
¥ But not apparently perfect Ñ about 90% correct
¥ Nevertheless, is widely taken to be true and is the basis for the Ògeneral linear modelÓ (GLM) in FMRI analysis

3 Brief Activations