neighbourdist for megplanar

[jan-mathijs schoffelen]

Dear Julian,

The unit of neighbourdist is according to the units in the gradiometer
array. The BTI convention is meters, so I think some value in the
order of 0.04 to 0.1 should be OK. (For the 248 channel 4D system I
always use a value of 0.037). Typically, I think it is optimal to have
just one rim of sensors (so don't take the value too big).


Cheers,

JM


On Jul 14, 2010, at 9:45 AM, Julian Keil wrote:

> Hi everyone,
>
> I was wondering what is a sensible neighbour distance for computing
> the megplanar from 4D148 data.
> The default is set to "4", but this this leads to on average 149
> neighbours per channel, which does not look right to me.
> Changing the distance to 0.1 reduces the number of neighbours to
> 5.5, yet I'm still unsure if this is the best/correct way.
>
> Thanks a lot
>
> Julian
>
>
>
> Dipl. Psych. Julian Keil
>
> OBOB-Lab
> University of Konstanz
> Department of Psychology
> P.O. Box D25
> 78457 Konstanz
> Germany
>
> Tel: ++49 - (0)7531 - 88 42 50
> Fax: ++49 - (0)7531 - 88 28 91
> Email: julian.keil at uni-konstanz.de
> Homepage: http://www.uni-konstanz.de/obob
>
>
>
>
>
>
>
> ----------------------------------
>
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>



Dr. J.M. (Jan-Mathijs) Schoffelen
Donders Institute for Brain, Cognition and Behaviour,
Centre for Cognitive Neuroimaging,
Radboud University Nijmegen, The Netherlands
J.Schoffelen at donders.ru.nl
Telephone: 0031-24-3668063


----------------------------------
The aim of this list is to facilitate the discussion between users of the FieldTrip  toolbox, to share experiences and to discuss new ideas for MEG and EEG analysis. See also http://listserv.surfnet.nl/archives/fieldtrip.html and http://www.ru.nl/neuroimaging/fieldtrip.
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