On 25 May 2010, at 00:02, Marco Loggia wrote:

Dear all,

I would like to create a peristimulus plot in which the datapoints represent % signal change from baseline.  What's the best way to calculate the 'baseline' (e.g. Averaging the values of 3-5 volumes prior to stimulus onset)?

Hi - that's quite common, yes - or take some lower percentile (e.g. 5th %) of the entire timeseries.

Cheers.



Thanks,

Marco



---------------------------------------------------------------------------
Stephen M. Smith, Professor of Biomedical Engineering
Associate Director,  Oxford University FMRIB Centre

FMRIB, JR Hospital, Headington, Oxford  OX3 9DU, UK
+44 (0) 1865 222726  (fax 222717)
[log in to unmask]    http://www.fmrib.ox.ac.uk/~steve
---------------------------------------------------------------------------