Hi Vitaly,

It seems to me that it would be much better to flip the 3D volume
over the medial slice than it would be to use the 1D file for the
opposite hemisphere.

The problem with using surface data to reflect it is that the nodes
are not symmetric across hemispheres. What you might be able to do
with the surface data is to negate the x-coordinate (assuming the
surfaces are aligned to Talairach datasets), but I don't know enough
about how the surface volumes are used to say for sure.

But using the surface for the opposite hemisphere is probably not the
best way to go. As an example, you could possibly use SurfMeasures
to display coordinates for surfaces from two hemispheres. Then you
could use 1deval to sum the two x-coordinates (which is equivalent to
negating the x-coordinate of one, and then taking their difference).
That would show you how far apart they are in the x-direction.

Realistically, you should then use 1deval to compute the 3D distance
between the nodes by taking the square root of the sum of squares of
the x, y and z differences. I expect that those numbers will be
annoyingly large, suggesting that you should reflect the data, instead.

I suspect that reflecting the x-coordinates of a surface is more work
than reflecting the data.

- rick