Hello all,
I was using the output of MELODIC to remove artifacts from fMRI data. I used a custom made algorithm to select the components which had to be removed from the data . For convenience reasons I wanted to subtract these components from the fMRI data outside the FSL pipeline.
So for each timeseries in the fMRI data I subtracted the matrix multiplication for the selected components within the 'melodic_mix' file and the corresponding values in the 'melodic_ic.nii' file. Now I noticed that this subtraction did not optimally reduce the variance in the timeseries and that I had to multiply the outcome of 'melodic_mix'#'melodic_ic.nii' with approximately 7.5 to get a more or less optimal reduction of the variance. This value was approximately the same for all subjects Is this correct? Does anyone know where this scaling comes from?
Kind regards,
Mathijs Raemaekers
Mathijs Raemaekers, PhD
Rudolf Magnus Institute, Department of Neurosurgery, UMC Utrecht
Visiting address: Universiteitsweg 100 (Stratenum), Room 4.113, Utrecht
Postadress: Postbus 85500, H.P. STR4.205, 3508 GA Utrecht
tel. 08875-50176
mob. 06-40964441
email. m.raemaekers-2@<mailto:[log in to unmask]>umcutrecht.nl
------------------------------------------------------------------------------
De informatie opgenomen in dit bericht kan vertrouwelijk zijn en is
uitsluitend bestemd voor de geadresseerde. Indien u dit bericht onterecht
ontvangt, wordt u verzocht de inhoud niet te gebruiken en de afzender direct
te informeren door het bericht te retourneren. Het Universitair Medisch
Centrum Utrecht is een publiekrechtelijke rechtspersoon in de zin van de W.H.W.
(Wet Hoger Onderwijs en Wetenschappelijk Onderzoek) en staat geregistreerd bij
de Kamer van Koophandel voor Midden-Nederland onder nr. 30244197.
Denk s.v.p aan het milieu voor u deze e-mail afdrukt.
------------------------------------------------------------------------------
This message may contain confidential information and is intended exclusively
for the addressee. If you receive this message unintentionally, please do not
use the contents but notify the sender immediately by return e-mail. University
Medical Center Utrecht is a legal person by public law and is registered at
the Chamber of Commerce for Midden-Nederland under no. 30244197.
Please consider the environment before printing this e-mail.
|