[Freesurfer] active volume of surface-based analysis

Hello, Freesurfer group, In the tutorial of surface-based fMRI analysis, the active volume are calculated from the entire depth of an given active vertex. I do not think it is the best way to measure it since no all activities occupy the entire depth of cortex. A logical way to get accurate active volume is measuring the active verities of multiple planes (e.g., at 0.1 mm distance) and then constructing the active volume from activity on these planes. A option (similar as --projfrac_max) can project the sum of all planes on the surface, and 3D active volume can be viewed in tkmedit.

Does Freesurfer currently have commands to achieve something like this procedure?

I am looking forward to hearing from you ASAP.

Thanks,

Xin