mention label support

README.md

@@ -13,6 +13,8 @@ GNU R package to read and write FreeSurfer neuroimaging file formats.
 
 * FreeSurfer surface file format: Contains a brain surface mesh. Such a mesh is defined by a list of vertices (each vertex is given by its x,y,z coords) and a list of faces (each face is given by three vertex indices). Currently only triangular meshes are implemented. An example file would be `surf/lh.white`. This format can be read and written.
 
+* FreeSurfer label file format: Contains a list of vertices included in a label. A label is like a mask, and is typically used to describe the vertices which are part of a certain brain region. An example file would be `label/lh.cortex.label`. This format can be read.
+
 
 ## Installation