I have created cortical surfaces corresponding to 25%, 50%, 75% of the cortex. Now I want to plot the T1/T2 values corresponding to these different layers.I believe I have to use mri_vol2surf. 

What options in the mri_vol2surf do I need to use to create these T1/T2 maps corresponding to these different layers of the cortex ?

Please let me know. Merry christmas and a happy New Year.

Thank you,

Ani