diff --git a/probtrackxOptions.h b/probtrackxOptions.h
index 0c19c10f51304448caad10ea0a2071f96a5c7eb6..78b0ea752a2489b5a4900354c0c93c3f39f754e7 100644
--- a/probtrackxOptions.h
+++ b/probtrackxOptions.h
@@ -178,10 +178,10 @@ class probtrackxOptions {
 	    string("Number of steps per sample"),
 	    false, requires_argument),
    c_thr(string("-c,--cthr"), 0.2, 
-	 string("Curvature threshold"), 
+	 string("Curvature threshold - default=0.2"), 
 	 false, requires_argument),
   fibthresh(string("--fibthresh"), 0.01, 
-	    string("volume fraction before subsidary fibre orientations are considered (def 0.01)"), 
+	    string("volume fraction before subsidary fibre orientations are considered default=0.01"), 
 	 false, requires_argument),
    steplength(string("--steplength"), 0.5, 
 	 string("steplength"),