 |
 |
Thank you very much. Dr Fatemeh Geranmayeh Wellcome Trust Clinical Research Fellow The Computational, Cognitive and Clinical Neuroimaging Laboratory Imperial College London Telephone : 020 7594 7994 From: Stephen Smith <[log in to unmask]<mailto:[log in to unmask]>> Reply-To: FSL - FMRIB's Software Library <[log in to unmask]<mailto:[log in to unmask]>> Date: Wed, 23 Jul 2014 10:18:04 +0100 To: <[log in to unmask]<mailto:[log in to unmask]>> Subject: Re: [FSL] using Eigenvariate in a PPI analysis instead of mean time series Hi - yes that should be fine - maybe even better than the mean wrt setting up a confound regressor. Yes I would think you should demean this. Cheers. On 23 Jul 2014, at 10:13, Geranmayeh, Fatemeh <[log in to unmask]<mailto:[log in to unmask]>> wrote: Dear experts I am running a PPI analysis in FEAT ad not sure if it is OK to use Eigenvariates derived from an ROI, instead of the mean time series, as the physiological EV. I have read Christian Beckman’s explanation on the difference between Eigenvariates and meants and it seams to me that Eigenvariates may be a better summary statistic to use. Would this be acceptable in the context of a PPI? https://www.jiscmail.ac.uk/cgi-bin/webadmin?A2=ind1301&L=FSL&P=R144619&1=FSL&9=A&I=-3&J=on&X=A618DE6A6FCE72AEB9&Y=fatemeh.geranmayeh00%40imperial.ac.uk&d=No+Match%3BMatch%3BMatches&z=4 If so, would you still recommend that the eigenvariate Physiological EV be “Zero-Meaned” ? Many thanks Fatemeh Dr Fatemeh Geranmayeh Wellcome Trust Clinical Research Fellow The Computational, Cognitive and Clinical Neuroimaging Laboratory Imperial College London Telephone : 020 7594 7994 --------------------------------------------------------------------------- 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]<mailto:[log in to unmask]> http://www.fmrib.ox.ac.uk/~steve --------------------------------------------------------------------------- Stop the cultural destruction of Tibet<http://smithinks.net>