Notes:
- [Display/Radiological menuitem](https://www.nitrc.org/forum/message.php?...) flips between neurological and radiological convention. The "L"
and "R" symbols change in the "2D Slices" panel to remind user of
current setting. Slices coordinates reflect MNI space (e.g. left
side of brain is negative regardless of viewing convention).
Rendering view not influenced: radiological view assumes camera is
anterior/inferior to object for coronal/sagittal views while
neurological assumes camera is posterior/superior.
- Better colorbars