[FieldTrip] Cluster analysis on correlation statistics

[Dr Christopher Brown]

Dear Eric, Tom, Arjen

 

Thanks for the information and it's good to know the functionality I need is
already there. Just to clarify, I understand the situation as thus (please
correct any errors of understanding):

-          The ft_statfun_indepsamplesregrT function can be used to
calculate parametric linear regression statistics with ivar as the
independent variable of interest, e.g. a behavioural variable across trials
or subjects, and uvar as units (e.g. trials or subjects).

-          The new ft_statfun_intersubcorr can calculate Spearman
correlation statistics between subjects (but not between trials), and
doesn't currently have a parametric (e.g., Pearson's) option, although this
appears to be covered by the ft_statfun_indepsamplesregrT function anyway.
By the way, in the ft_statfun_intersubcorr description/instructions, some of
the text appears to refer to ft_statfun_depsamplesT instead. Can I assume
that ivar is in fact the behavioural variable of interest rather than
"conditions that must be compared" as currently stated? Also, what is the
reason this function cannot be used across trials within a subject?

 

Best wishes

Chris

 

Dr Christopher Brown 

Research Associate | CamPain Research Group | Department of Anaesthesia |
University of Cambridge 

Box 93 
Addenbrooke's Hospital 
Hills Road 
Cambridge CB2 0QQ 

01223 256 995

 

From: fieldtrip-bounces at science.ru.nl
[mailto:fieldtrip-bounces at science.ru.nl] On Behalf Of Tom Marshall
Sent: 08 December 2014 15:10
To: FieldTrip discussion list
Subject: Re: [FieldTrip] Cluster analysis on correlation statistics

 

Hm... it seems that I may have reinvented the wheel (or perhaps invented a
cruder wheel before Eric and co provided this more streamlined one).

Eric, can indepsamplesregrT also compute nonparametric correlation
coefficients (eg Spearman)?

Best,
Tom

On 12/8/2014 3:56 PM, Maris, E.G.G. (Eric) wrote:

Hi Chris,

 

Just to clarify my last email: I'm referring to correlation between either
single trial data within subject, or averaged ERPs across subjects, with a
behavioral variable. Not linear regression across conditions as is already
implemented in the ft_statfun_depsamplesregrT function.

 

For correlating/regressing single trial data of a single subject, you use
the ft_statfun_indepsamplesregrT (with the units-of-observations being the
trials, which each correspond to one column of your design matrix). 

 

For correlating/regressing subject-averaged data of a group of subjects, you
also use the ft_statfun_indepsamplesregrT (with the units-of-observations
being the subjects, which each correspond to one column of your design
matrix).  Note, in this case your behavioral data (accuracy or RT) or also
subject averages.

 

Best,

 

Eric Maris

 

 

 

  _____  

Van: Dr C A Brown [ <mailto:cb802 at cam.ac.uk> cb802 at cam.ac.uk]
Verzonden: zaterdag 6 december 2014 12:33
Aan:  <mailto:fieldtrip at science.ru.nl> fieldtrip at science.ru.nl
Onderwerp: Re: [FieldTrip] Cluster analysis on correlation statistics

Hello again,

 

Just to clarify my last email: I'm referring to correlation between either
single trial data within subject, or averaged ERPs across subjects, with a
behavioral variable. Not linear regression across conditions as is already
implemented in the ft_statfun_depsamplesregrT function.

 

Many thanks

Chris 

 

Dr Christopher Brown

Research Associate

 

Sent from a mobile device, please excuse my brevity.

 

----- Reply message -----
From: "Christopher Brown"  <mailto:cb802 at cam.ac.uk> <cb802 at cam.ac.uk>
To:  <mailto:fieldtrip at science.ru.nl> <fieldtrip at science.ru.nl>
Subject: Cluster analysis on correlation statistics
Date: Sat, Dec 6, 2014 07:49

 

Dear all

I would like to use the cluster analysis functions in Fieldtrip on
correlation statistics. I note there has been some discussion about this on
this list in the past but I haven't come across the necessary
ft_statfun_corr function to allow this analysis. It would be great if
somebody has this code and could share it with me; otherwise, I will embark
on writing it myself and sharing my results with everyone for feedback.
Being new to Fieldtrip I would greatly appreciate any collaborative help
with this. May I check my understanding on something before getting started:
To allow for multiple comparisons correction using monte carlo for example,
as part of a cluster analysis, I presume the output of the function must be
t values rather than correlation coefficients? Any other hints as to how to
write this are most welcome.

Kind regards

Chris

-- 

Dr Christopher Brown 
Research Associate | CamPain Group | Division of Anaesthesia | School of
Clinical Medicine | University of Cambridge 
 
Box 93 
Addenbrooke's Hospital 
Hills Road 
Cambridge CB2 0QQ 
 
01223 256 995






_______________________________________________
fieldtrip mailing list
fieldtrip at donders.ru.nl <mailto:fieldtrip at donders.ru.nl> 
http://mailman.science.ru.nl/mailman/listinfo/fieldtrip

 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.science.ru.nl/pipermail/fieldtrip/attachments/20141209/867e24db/attachment-0002.html>