diff --git a/NOTES b/NOTES
index f3a6ed8f2e4aa3d7d677316553b1f41a0a94a03b..3f135282520475e7d179e36f82592acdd9166ee7 100644
--- a/NOTES
+++ b/NOTES
@@ -1,3 +1,13 @@
 
 siena_diff - cannot compile with optimisation turned on (gcc bug)
 
+37744 nonzero voxels in avg152T1_edges
+say 20000 real edge voxels (ignoring corner points)
+
+smooth with sigma=10mm=5voxels
+thus 1 resel = approx 100 voxels
+but intrinsic smoothness factor = 2
+-> 200 voxels
+
+thus bonf correct by factor of 100
+thus uncorrected 0.05 -> 0.0002 -> z=3.7
diff --git a/siena_diff.c b/siena_diff.c
index bfb8ad63c62d51e7d2da2a9229fa24e59c9e20c3..fe916eca8a4748b57e9fc8e354b01a0e4c0df682 100644
--- a/siena_diff.c
+++ b/siena_diff.c
@@ -601,6 +601,7 @@ seg1=im.i;
 
 for(x=0;x<size;x++)
   if (seg1[x]>1)
+     /*if (seg1[x]>2)*/
     seg1[x]=1;
   else
     seg1[x]=0;