diff --git a/books/structural_imaging/brain_extraction_different_tools.ipynb b/books/structural_imaging/brain_extraction_different_tools.ipynb
index ed787f84..f88ee3bf 100644
--- a/books/structural_imaging/brain_extraction_different_tools.ipynb
+++ b/books/structural_imaging/brain_extraction_different_tools.ipynb
@@ -4,7 +4,7 @@
"cell_type": "markdown",
"metadata": {},
"source": [
- " "
+ " "
]
},
{