Update 'README.md'

README.md

@@ -14,7 +14,7 @@ If you wish to use the data in any form or want to collaborate, please get in to
 
 Calcium fluorescence signals of hundreds of simultaneously imaged neurons in mouse retrosplenial cortex during a virtual navigation task (running on a linear treadmill track with head-fixed), from different experimental groups of animals: control mice, mice with unilateral hippocampus lesion (uni), and mice with bilateral hippocampus lesions (bi).
 
-Each element in the cell array corresponds to data from one animal with the suffix indicating experimental group.
+Each element in the .mat cell array corresponds to data from one animal with the suffix indicating experimental group.
 
 Data structure explained below: