diff --git a/geneExpressionData/AtlasViewerFormat/README.md b/geneExpressionData/AtlasViewerFormat/README.md
index 254475beafdeb29ddfe7f97a1e0991b9c732c1da..1ba1793f53fa7fc3dc5f71784e61d3b9f06a42ba 100644
--- a/geneExpressionData/AtlasViewerFormat/README.md
+++ b/geneExpressionData/AtlasViewerFormat/README.md
@@ -8,3 +8,12 @@ Drag and drop the segmentation file and the visualization widget and then drag
 and drop the pattern file. Select the genes to visualize form the right pane and
 click "Atlas gene expression" button from the AtlasViewer menu.
 
+To read the .pat files in the folders:
+
+import cPickle
+ fobj = file("patternFileName.pat")
+ patterns = cPickle.load(fobj)
+ fobj.close()
+ 
+ #patterns is a Python dictionary whose keys are genes and values are cell 
+ labels expressing the gene.
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