[pymvpa] surface-based analysis in PyMVPA.

[Michael Hanke]

Hi,

On Tue, Jul 05, 2011 at 07:59:10PM +0800, Zhen Zonglei wrote:
> Dear PyMVPAer:
> 
> I have two questions about surface-based analysis in PyMVPA.
> 
> 1.      Can the dataset mapper of PyMVPA handle surface-based data
> automatically?

As of today, there is no dedicated mapper for surface data. However, in
most cases (if just access to the data is required) that is not
necessary, because surface data is essentially already a 2D matrix that
can be wrapped in a dataset right away -- no need for mapping.

> 2.      Is there a convenient way to do surface-based searchlight analysis
> in PyMVPA?

Well, no -- or not entirely. The missing piece is a function that
enriches the dataset of surface data with geometry information for the
nodes. Like for the volumetric data, we need a coordinate per feature
(or matrix column) to feed to the distance computing/checking machinery.

I think the pieces are or ready to be stitched together. NiBabel has
support for GIFTI data, PyMVPA interfaces to NiBabel, PyMVPA as a
generic-enough way to generate searchlight ROIs on arbitrary
dimensions/spaces -- it just needs some glue.

I'd expect that sometime in the second half of this years, one of us
will implement that, but anyone is welcome to contribute that code!

Michael

-- 
Michael Hanke
http://mih.voxindeserto.de