[FieldTrip] Why the general use of parametric test as observed test statistic for permutation cluster tests?

[Peter Goodin]

Hi Fieldtrip list, 

I'm just wondering if someone can explain if there is a reasoning behind the general use of a parametric test to calculate the initial step in the permutation cluster test and not a non-parametric test (e.g t-test over Mann Whitey U)? Is it just due to the assumption of a Gaussian distribution or is there something deeper going on? 

Thanks, 

Peter

_______________________
Peter Goodin, 
BSc (Hons), Ph.D Candidate (submitted).

Brain and Psychological Sciences Research Centre (BPsych)
Swinburne University, 
Hawthorn, Vic, 3122
http://www.swinburne.edu.au/swinburneresearchers/index.php?fuseaction=profile&pid=4149

Monash Alfred Psychiatry Research Centre (MAPrc)
Level 4, 607 St Kilda Road, 
Melbourne 3004