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  2004

FSL 2004

Options

Subscribe or Unsubscribe

Subscribe or Unsubscribe

Log In

Log In

Get Password

Get Password

Subject:

Re: 3-level GLM with single subject data?

From:

Stephen Smith <[log in to unmask]>

Reply-To:

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

Date:

Tue, 13 Jan 2004 01:27:38 +0000

Content-Type:

TEXT/PLAIN

Parts/Attachments:

Parts/Attachments

TEXT/PLAIN (88 lines)

Hi Thomas,

Probably this is best run all at second-level, and with the standard
(mixed-effects) framework, so that you are asking the question - "are the
fitted effects at second-level greater than the session variability?". So
you would put the 3*6 first-level analyses into the second-level design.

Your covariate of no interest looks ok. You probably also want to take out
the mean effect with an EV of all 1s. Then your main question should be
orthogonalised with respect to this, i.e., demeaned.

Regards, Steve.



On Wed, 7 Jan 2004, Thomas Mierdorf wrote:

> Hi,
>
> I am wondering if it might be possible to use a
> three level mixed-effects GLM to analyse my
> single-subject repeated-measure fMRI data which
> looks like this:
>
> First-level:
> - blockdesign (106 scans)
> - three conditions repeated three times each
>    + 7 confounds (incl. headmovement estimates)
>
> Second-level:
> - the measurement was repeated twice resulting in
> three sessions
> - a covariate of no interest at this level could
> be "adaption" (1 0 -1)
>
> Third-level:
> - the three sessions were repeated six times
> seperated by a week each
> - after the first week we introduced a treatment
> which stopped right before the fifth week
> - a covariate of no interest at this level could be
> again "adaption" (5 3 1 -1 -3 -5)
> - I want to test for positive or negative BOLD
> responses which change with treatment, i.e. either
> look at differences between all of the weeks or
> use a covariate which resembles our hypothesis:
> 1-1-2-3-4-2
>
> Does this make sense while all data is coming from
> a single subject? How do I calculate the effective
> degrees of freedom (which are hopefully not 6 weeks
> minus 2 covariates = 4 as in "random effects"
> analysis)?
>
> Unfortunately, the control condition turned out to
> change with treatment too, therefore I am not able
> to use the contrast "(A or B) > C" at the first-level,
> but only "(A or B) > 0" or "(A or B) < 0". Apart
> from introducing the problem of intra-subject
> variability of activation (which would have been
> controlled by the control condition), does this
> complicate anything?
>
> I would be grateful for any advice.
>
> All the best,
> Thomas
>
>
>  -------------------------------
>  Thomas Mierdorf, Dipl. Psych.
>
>  Institute of Experimental Psychology
>  Heinrich-Heine-University, D-40225 Duesseldorf, Germany
>
>  voice: ++492118112010;  fax: ++492118114522
>  email: [log in to unmask]
>

 Stephen M. Smith  DPhil
 Associate Director, FMRIB and Analysis Research Coordinator

 Oxford University Centre for Functional MRI of the Brain
 John Radcliffe Hospital, Headington, Oxford OX3 9DU, UK
 +44 (0) 1865 222726  (fax 222717)

 [log in to unmask]  http://www.fmrib.ox.ac.uk/~steve

Top of Message | Previous Page | Permalink

JiscMail Tools


RSS Feeds and Sharing


Advanced Options


Archives

January 2020
December 2019
November 2019
October 2019
September 2019
August 2019
July 2019
June 2019
May 2019
April 2019
March 2019
February 2019
January 2019
December 2018
November 2018
October 2018
September 2018
August 2018
July 2018
June 2018
May 2018
April 2018
March 2018
February 2018
January 2018
December 2017
November 2017
October 2017
September 2017
August 2017
July 2017
June 2017
May 2017
April 2017
March 2017
February 2017
January 2017
December 2016
November 2016
October 2016
September 2016
August 2016
July 2016
June 2016
May 2016
April 2016
March 2016
February 2016
January 2016
December 2015
November 2015
October 2015
September 2015
August 2015
July 2015
June 2015
May 2015
April 2015
March 2015
February 2015
January 2015
December 2014
November 2014
October 2014
September 2014
August 2014
July 2014
June 2014
May 2014
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


JiscMail is a Jisc service.

View our service policies at https://www.jiscmail.ac.uk/policyandsecurity/ and Jisc's privacy policy at https://www.jisc.ac.uk/website/privacy-notice

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