Robert Oostenveld r.oostenveld at FCDONDERS.RU.NL
Fri Aug 12 14:02:20 CEST 2005

Hi Sanja,

On 11-aug-2005, at 22:52, Sanja Kovacevic wrote:
> I am trying to use meginterpolate/freqanalysis/combineplanar to get
> the tfr
> data in the planar gradiometer system, instead of the original 275
> ch axial.
> However, combineplanar needs planarchannelset, but this function is
> not
> included in the 20050811 distribution. Could you include this
> function in
> the next distribution?

Please find the function attached to this mail. I will add it to the
next daily releases, sorry that it was missing.

The attached version however does not include the 275ch CTF system
yet, but it is easy to add. You basically only have to make a table
with the planar channel labels that should be combined, and the name
of the combined channel (i.e. the original name). I would appreciate
it if you would send me the table information for the CTF 275 system,
I will then update the release version as well.

> I have a set of questions related to meginterpolate: Can CTF274.lay
> be used
> for ploting the planar data? Should I use a default single sphere
> model for
> each subject or a single sphere model particular for a subject for
> realignment? Should "nominal" sensor locations be used as a
> template for
> each subject, or do you recommend taking an average across subjects
> for the
> template?

Yes, but only for combineplanar'ed data in combination with
topoplotTFR. It is conceptually not possible to make a topography of
the "raw" planar data itself, but you can do a multiplotER and
multiplotTFR of the planar data. However, that would require another
lay file. The NM122all.lay file is one for the Neuromag system that
plots the 122 planar channels at 66 locations, with horizontal and
vertical channel next to each other.

If you do not specify a layout in the cfg of multiplotTFR, the
private subfunction createlayout will construct a layout on the fly
based on the gradiometer positions. Usually the plotting is more
controlled with a manually eddited layout file, but the automatic one
can serve as starting point. Looking into the code, I now realise
that there still are some loose ends. The megplanar function does not
return the planar gadiometer definition. Please have a look at the
private functions axial2planar and createlayout, and use them
together to construct a planar layout file.

best regards,
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