I found it
Posted by Miri Barak on September 01, 2004
In Reply to: Furrowed brow posted by Miri Barak on September 01, 2004
: : : Hello
: : : A *brow squint* is a nonmanual signal in sign language.
: : : Is it the same as half closed eyes?
: : : Thank you
: : When you're puzzled, you put on an expression with a furrowed brow. This has the effect of making the eyes narrower. Does this fit the situation?
: Thank you Henry. I'm not sure. In Sign this signal indicates a negation. I just don't understand how can one squint a brow unless he is partly closing his eyes.
Thank you Henry, I found a site where they show a presentation of negation in sign language and it is a narrowing fo one eye.