diff --git a/vecreg.cc b/vecreg.cc
index 4d2636f9403bbb189d5c8f4a763830382d71408e..7ddb54143a66105c947461358429296da0b807bb 100755
--- a/vecreg.cc
+++ b/vecreg.cc
@@ -40,7 +40,7 @@ Option<string> matrix(string("-t,--affine"),string(""),
 Option<string> warp(string("-w,--warpfield"),string(""),
 		       string("filename of 4D warp field for nonlinear registration"),
 		       false,requires_argument);
-Option<string> interpmethod(string("--interp"),string("nearestneighbour"),
+Option<string> interpmethod(string("--interp"),"",
 		       string("interpolation method : nearestneighbour (default) or trilinear or sinc"),
 		       false,requires_argument);
 Option<string> maskfile(string("-m,--mask"),string(""),