plotting

[Punita]

Hello,
I am new to this group.  I was just wondering if there was a simple method 
in fieldtrip that would allow me to plot surface potential data on a 
spherical head surface.  As for my data - I have 3 arrays containing the x, 
y, and z coordinates on the surface of the head, and a 4th array that 
contains values of the potentials at these specified locations.  
Any help or pointers would be deeply appreciated.
Thank you,
Punita