fmri_mni2sub
============

.. currentmodule:: fmri_toolbox

Description
-----------
FMRI_MNI2SUB  Converts MNI coordinates (mm) to voxel subscripts.
Converts one or more MNI152 coordinates (in mm) to voxel subscripts in the
91x109x91 MATLAB 1-based subscript space, using the standard 2mm MNI152
template. Rounds to the nearest voxel centre.

Usage
-----
.. code-block:: matlab

    sub = fmri_mni2sub(mni)

Inputs
------
- **MNI**: MNI coordinates in mm, (N x 3) matrix: [x1 y1 z1; x2 y2 z2; ...].

Outputs
-------
- **SUB**: Voxel subscripts (rounded), (N x 3) matrix: [x y z].
- **1**: based MATLAB indices, x in [1 91], y in [1 109], z in [1 91].

Examples
--------
.. code-block:: matlab

    sub = fmri_mni2sub([0 0 0]);             % returns [46 64 37]
    sub = fmri_mni2sub([-42 -18 60]);        % motor cortex
    mask = fmri_spheremask(fmri_mni2sub([20 -58 18]), 5);

Notes
-----
- MNI [0 0 0] maps to subscript [46 64 37].
- Coordinates outside the brain volume are not clipped — use with care.
- Inverse function: fmri_sub2mni.

See Also
--------
- fmri_sub2mni
- fmri_mni2tal
- fmri_spheremask
- fmri_regionmask