JiscMail Logo
Email discussion lists for the UK Education and Research communities

Help for FSL Archives


FSL Archives

FSL Archives


FSL@JISCMAIL.AC.UK


View:

Message:

[

First

|

Previous

|

Next

|

Last

]

By Topic:

[

First

|

Previous

|

Next

|

Last

]

By Author:

[

First

|

Previous

|

Next

|

Last

]

Font:

Proportional Font

LISTSERV Archives

LISTSERV Archives

FSL Home

FSL Home

FSL  August 2007

FSL August 2007

Options

Subscribe or Unsubscribe

Subscribe or Unsubscribe

Log In

Log In

Get Password

Get Password

Subject:

Re: multi-session / subject MELODIC

From:

Christopher Bell <[log in to unmask]>

Reply-To:

FSL - FMRIB's Software Library <[log in to unmask]>

Date:

Mon, 20 Aug 2007 16:50:14 -0500

Content-Type:

text/plain

Parts/Attachments:

Parts/Attachments

text/plain (91 lines)

Hello,

I similarly have a resting-state data set with two separate runs for the 
same group of subjects. I have a couple questions based upon these posts. 
How would I specify the contrasts to look for differences in the amount of 
variance of the associated time-courses? This is just the concatenated data 
from time1 contrasted to the concatenated data for time2 (for example)? 
What would the GLM be? ...time1 and time2 concatenated together? Also, does 
anybody have any recommendations on how to look for spatial map differences 
in the new multi-session melodic analysis? ...I didn't realize the spatial 
maps were "effectively fixed" in a multi-session concatenated or TICA 
analysis. Thanks for your help.

Chris Bell

On Aug 16 2007, Vitaly Napadow wrote:

>thank you, Christian. I think I understand - for my purposes, to test for 
>spatial (not tempopral) differences, I will continue with my past 
>approach...
>
>regards,
>
>vitaly
>
>
>On Thu, 16 Aug 2007, Christian Beckmann wrote:
>
>> Hi
>>
>> On 15 Aug 2007, at 17:20, Vitaly Napadow wrote:
>>
>>> hi all
>>> 
>>> firstly, thanks for finally pushing this out. i think we were all 
>>> chomping at the bit looking forward to the new release and it feels 
>>> great to finally play with the new tools.
>>> 
>>> i had completed an analysis of resting state data but want to go back 
>>> and try the new tools now. i have 15 subjects and two separate rest 
>>> runs that i am comparing from each subject. i assume i want to use 
>>> Multi-session temporal concatenation to contrast the two rest runs.
>>
>> Yes, temporal concatenation is probably what you want, though you still 
>> will need to decide on what exactly you want to compare between runs, 
>> e.g. the amount of variance in the associated time course (as a measure 
>> of volatility) or any other quantity you could come up with such as mean 
>> level
>>
>>> so as not to compare apples to oranges, i want to contrast specific 
>>> resting state networks. my question is, if i specify and 2nd level 
>>> design.mat and design.con file with a 1 -1 contrast how will i know 
>>> which resting state networks (evident on group maps) are associated 
>>> with or correspond to which 2nd level output components?
>>
>> Don't quite understand the question. In the new release version you 
>> have the option of testing (in the GLM sense) each associated time 
>> course and each associated session/subject mode using design and 
>> contrast matrices. The GLm fit will be performed separately for each 
>> time course and/or subject session mode vector.
>>
>>> 
>>> alternatievly, if i already did single-subject analyses and have mixing
>>> matrices etc with components corresponding to known resting networks and
>>> which can be pulled out to input into a 2nd level group analysis, are my
>>> options to contrast on a 2nd level the same as before?
>>
>> fundamentally yes, the main difference being that in the case of 
>> separate analyses you're bound to have differences in e.g. the 
>> default-mode network between subjects. In the case of temporal 
>> concatenation or full TICA you effectively fix the spatial maps to be 
>> identical and only allow the time courses to be different. hope this 
>> helps Christian
>>
>>> thanks
>>> 
>>> vitaly
>>> 
>>
>> ____
>> Christian F. Beckmann
>> University Research Lecturer
>> Oxford University Centre for Functional MRI of the Brain (FMRIB)
>> John Radcliffe Hospital, Headington, Oxford OX3 9DU, UK.
>> [log in to unmask]	http://www.fmrib.ox.ac.uk/~beckmann
>> tel: +44 1865 222551			fax: +44 1865 222717
>>
>>
>>
>
>

Top of Message | Previous Page | Permalink

JISCMail Tools


RSS Feeds and Sharing


Advanced Options


Archives

April 2014
March 2014
February 2014
January 2014
December 2013
November 2013
October 2013
September 2013
August 2013
July 2013
June 2013
May 2013
April 2013
March 2013
February 2013
January 2013
December 2012
November 2012
October 2012
September 2012
August 2012
July 2012
June 2012
May 2012
April 2012
March 2012
February 2012
January 2012
December 2011
November 2011
October 2011
September 2011
August 2011
July 2011
June 2011
May 2011
April 2011
March 2011
February 2011
January 2011
December 2010
November 2010
October 2010
September 2010
August 2010
July 2010
June 2010
May 2010
April 2010
March 2010
February 2010
January 2010
December 2009
November 2009
October 2009
September 2009
August 2009
July 2009
June 2009
May 2009
April 2009
March 2009
February 2009
January 2009
December 2008
November 2008
October 2008
September 2008
August 2008
July 2008
June 2008
May 2008
April 2008
March 2008
February 2008
January 2008
December 2007
November 2007
October 2007
September 2007
August 2007
July 2007
June 2007
May 2007
April 2007
March 2007
February 2007
January 2007
2006
2005
2004
2003
2002
2001


WWW.JISCMAIL.AC.UK

Secured by F-Secure Anti-Virus CataList Email List Search Powered by the LISTSERV Email List Manager