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Dear fieldtrippers,<br>
I'm still in need of an advise on the issue below. Any help would be
greatly appreciated!!<br>
<br>
<br>
<br>
<br>
<br>
<meta http-equiv="Content-Type" content="text/html;
charset=ISO-8859-1">
Dear Robert and Stephan,<br>
Thank you for your replies. <br>
I guess I use what Robert called the 'regular' 3D grid, but I'm not
quite sure.<br>
<br>
The structures of my headmodel and leadfield matrix are the
following (based on data from a BEM standard file):<br>
<br>
vol = <br>
<br>
bnd: [1x3 struct]<br>
cond: [0.3300 0.0041 0.3300]<br>
mat: [3000x3000 double]<br>
type: 'dipoli'<br>
<br>
<br>
<br>
ldf = <br>
<br>
xgrid: [-65 -58 -51 -44 -37 -30 -23 -16 -9 -2 5 12 19 26 33
40 47 54 61 68]<br>
ygrid: [-107 -100 -93 -86 -79 -72 -65 -58 -51 -44 -37 -30
-23 -16 -9 -2 5 12 19 26 33 40 47 54 61 68 75]<br>
zgrid: [-52 -45 -38 -31 -24 -17 -10 -3 4 11 18 25 32 39 46
53 60 67 74 81]<br>
dim: [20 27 20]<br>
pos: [10800x3 double]<br>
inside: [1x5739 double]<br>
outside: [1x5061 double]<br>
leadfield: {1x10800 cell}<br>
cfg: [1x1 struct]<br>
<br>
<br>
<b>In any case, I still don't quite understand how to calculate the
neighbours to each voxel.<br>
</b>By saying that the "neighbours are trivial to find and you do
not have to specify a structure", do you mean that I don't need to
define the cfg.neighbours property at all (given that I do use a
regular 3D grid)?<br>
<br>
Thanks again for your help, cheers,<br>
Ulrich <br>
<br>
<br>
<br>
<br>
<br>
On 31.01.2012 21:48, <a moz-do-not-send="true"
class="moz-txt-link-abbreviated" href="mailto:smoratti@psi.ucm.es">
smoratti@psi.ucm.es</a> wrote:
<blockquote
cite="mid:b22e6875075e4c5dace4ee98aae1864b@EXCCAHT-4.mail.uke.ads"
type="cite">
Dear Robert,
<div><br>
</div>
<div>To do clustering on a 3D source surface I always had to
"trick" field trip and squeezed the 3D source surface data into
a ERF structure treating the 3D surface points as sensors. Then
by triangulation I found the neighbors. However, if there is a
more elegant method implemented in ft_sourcestatistc, I would be
very interested to know how to do it. Where can I find some
hints on that?</div>
<div><br>
</div>
<div>Best,</div>
<div><br>
</div>
<div>Stephan</div>
<div><br>
</div>
<div>
<div><span class="Apple-style-span" style="border-collapse:
separate; color: rgb(0, 0, 0); font-family: Helvetica;
font-style: normal; font-variant: normal; font-weight:
normal; letter-spacing: normal; line-height: normal;
orphans: 2; text-align: -webkit-auto; text-indent: 0px;
text-transform: none; white-space: normal; widows: 2;
word-spacing: 0px; -webkit-border-horizontal-spacing: 0px;
-webkit-border-vertical-spacing: 0px;
-webkit-text-decorations-in-effect: none;
-webkit-text-size-adjust: auto; -webkit-text-stroke-width:
0px; font-size: medium; ">
<div>
<div>________________________________________________________</div>
<div>Stephan Moratti, PhD<br>
<br>
</div>
<div>see also: <a moz-do-not-send="true"
href="http://web.me.com/smoratti/">http://web.me.com/smoratti/</a><br>
<br>
</div>
<div>Universidad Complutense de Madrid</div>
<div>Facultad de Psicología</div>
<div>Departamento de Psicología Básica I</div>
<div>Campus de Somosaguas</div>
<div>28223 Pozuelo de Alarcón (Madrid)</div>
<div>Spain</div>
<div><br>
</div>
<div>and</div>
<div><br>
</div>
<div>Center for Biomedical Technology</div>
<div>Laboratory for Cognitive and Computational
Neuroscience</div>
<div>Parque Científico y Tecnológico de la Universidad
Politecnica de Madrid<br>
Campus Montegancedo</div>
<div>28223 Pozuelo de Alarcón (Madrid)</div>
<div>Spain<br>
<br>
<br>
email: <a moz-do-not-send="true"
href="mailto:smoratti@psi.ucm.es">smoratti@psi.ucm.es</a><br>
Tel.: +34 679219982</div>
</div>
</span></div>
<br>
<div>
<div>El 31/01/2012, a las 15:37, Robert Oostenveld escribió:</div>
<br class="Apple-interchange-newline">
<blockquote type="cite">
<div style="word-wrap: break-word; -webkit-nbsp-mode: space;
-webkit-line-break: after-white-space; ">
Dear Ulrich
<div><br>
</div>
<div>If your source locations are defined on a regular 3D
grid that can be represented as volume, then the
neighbours are trivial to find and you do not have to
specify a structure for the neighbours. </div>
<div><br>
</div>
<div>If you have done source reconstruction on a 3D folded
cortical sheet that is defined by a triangulated
surface, then it is also possible to cluster along the
surface. I don't know the details for the cortical sheet
clustering from the top of my head, if you are
interested please let me know and I'll look them up. </div>
<div><br>
</div>
<div>best</div>
<div>Robert</div>
<div><br>
</div>
<div><br>
</div>
<div><br>
</div>
<div><br>
<div>
<div>On 30 Jan 2012, at 16:58, Pomper, Ulrich wrote:</div>
<br class="Apple-interchange-newline">
<blockquote type="cite"><span class="Apple-style-span"
style="border-collapse: separate; font-family:
Helvetica; font-style: normal; font-variant:
normal; font-weight: normal; letter-spacing:
normal; line-height: normal; orphans: 2;
text-align: -webkit-auto; text-indent: 0px;
text-transform: none; white-space: normal; widows:
2; word-spacing: 0px;
-webkit-border-horizontal-spacing: 0px;
-webkit-border-vertical-spacing: 0px;
-webkit-text-decorations-in-effect: none;
-webkit-text-size-adjust: auto;
-webkit-text-stroke-width: 0px; font-size: medium;
">Dear Jörn,<br>
Thanks for you reply. I did mean source-level, so
like you said, I am trying to define the
neighbouring voxels for each voxel.<br>
As far as I understand, leaving cfg.neighbours
blank means that the clustering is done over the
time and frequency dimensions only, not over
space.<span class="Apple-converted-space"> </span><br>
The FT help reads:<span
class="Apple-converted-space"> </span><br>
%If you specify an empty neighbourhood structure,
clustering will only be done in frequency and time
(if available) and not over neighbouring channels.<br>
<br>
Has anybody done clustering in source space using
all three dimensions and could explain how this
works?<br>
Cheers,<span class="Apple-converted-space"> </span><br>
Ulrich<br>
<br>
</span></blockquote>
</div>
<br>
</div>
</div>
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<font face="monospace"><br>
--<br>
Pflichtangaben gemäß Gesetz über elektronische Handelsregister und
Genossenschaftsregister sowie das Unternehmensregister (EHUG):<br>
<br>
Universitätsklinikum Hamburg-Eppendorf; Körperschaft des
öffentlichen Rechts; Gerichtsstand: Hamburg<br>
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