It's not surprising that the amplitude of the model differs for 200ms vs.
1200ms events. This is the basis for the difference in sensitivity between
event-related designs (ie short events) vs. blocked-designs (which are
equivalent to long events). If you don't expect your BOLD response to
exhibit this effect over this particular range, then by all means rescale
the amplitude. On the other hand, it is important to note that this is the
expected behaviour of the model.
Joseph T. Devlin, Ph. D.
FMRIB Centre, Dept. of Clinical Neurology
University of Oxford
John Radcliffe Hospital
Headley Way, Headington
Oxford OX3 9DU
Phone: 01865 222 738
Email: [log in to unmask]