Yes. This is the root cause. Since you have no data, the smoothing ends up pulling in the closest data. Since you are not analyzing areas outside of the brain, then the DARTEL smoothing process is fine.

Best Regards, Donald McLaren
=================
D.G. McLaren, Ph.D.
Research Fellow, Department of Neurology, Massachusetts General Hospital and
Harvard Medical School
Postdoctoral Research Fellow, GRECC, Bedford VA
Website: http://www.martinos.org/~mclaren
Office: (773) 406-2464
=====================
This e-mail contains CONFIDENTIAL INFORMATION which may contain PROTECTED
HEALTHCARE INFORMATION and may also be LEGALLY PRIVILEGED and which is
intended only for the use of the individual or entity named above. If the
reader of the e-mail is not the intended recipient or the employee or agent
responsible for delivering it to the intended recipient, you are hereby
notified that you are in possession of confidential and privileged
information. Any unauthorized use, disclosure, copying or the taking of any
action in reliance on the contents of this information is strictly
prohibited and may be unlawful. If you have received this e-mail
unintentionally, please immediately notify the sender via telephone at (773)
406-2464 or email.

On Thu, Sep 11, 2014 at 9:45 PM, Jeff Browndyke <[log in to unmask]> wrote:
Thanks to all for the suggestions.  I’ll give regular smoothing a shot and see if that works.

The only thing that I can see that may account for why some of my subjects have the “wiping” and others do not is the amount of clearance there is in the z-plane of the original bounding box.  It appears that if there is signal that touches upon or gets very close to the original bounding box, this “wiping” type artifact is generally produced.   Subject EPI images well below the bounding box edge have none of this type of DARTEL processing error.

Warm regards to all,
Jeff



On Sep 11, 2014, at 9:26 AM, YAN Chao-Gan <[log in to unmask]> wrote:

Hi Sandra,

I think these two posts are related: 

Holes after using DARTEL normalization

Problem with normalization

I think the traditional smooth can fix that, but not the DARTEL smooth. I believe the latter one happens in original space and thus can not fill the holes.

Best,

Chao-Gan





On Thu, Sep 11, 2014 at 8:25 AM, Sandra Tamm <[log in to unmask]> wrote:
Dear everyone,

I sent the recent mail to this list. I agree that it is not a coregistration problem (at least not in my case). I also found out that the problem seems to occur in the smoothing step in DARTEL, because if I perform normalization and set the smoothing kernel to 0 0 0  and then perform the standard smoothing in SPM I don’t get the artifacts.

Hope that can help a bit!
Sandra


On 11 sep 2014, at 14:18, Helmut Nebl <[log in to unmask]> wrote:

> Dear Jeff,
>
>
> your screenshot looks similar to that in a recent message https://www.jiscmail.ac.uk/cgi-bin/webadmin?A2=spm;79d22bc2.1408 , so maybe there's a bug somewhere?
>
> Unfortunately I can't help, but at least I don't think it's due to bad coregistration between structure and functional data or structure and template as stated in that thread, as your image should be distorted/incorrectly stretched globally then.
>
>
> Hope someone else can provide some solution,
>
> Helmut