| Animal Type | 
  C57BL/6 wild type (n=5) | 
  C57BL/6 wild type (n=4) | 
  C57BL/6 wild type (n=5) | 
    
   
  | Age at Exam
    (Post-natal Day)     | 
  Group # | 
  1 | 
  2 | 
  3 | 
    
   
  | 4 | 
    | 
    | 
    | 
    
   
  | 6 | 
    | 
    | 
    | 
    
   
  | 10 | 
    | 
    | 
    | 
    
   
  | 11 | 
    | 
    | 
    | 
    
   
  | 12 | 
    | 
    | 
    | 
    
   
  | 14 | 
    | 
    | 
    | 
    
   
  | 15 | 
    | 
    | 
    | 
    
   
  | 18 | 
    | 
    | 
    | 
    
   
  | 19 | 
    | 
    | 
    | 
    
   
  | 21 | 
    | 
    | 
    | 
    
   
  | 22 | 
    | 
    | 
    | 
    
   
  | 24 | 
    | 
    | 
    | 
    
   
  | 25 | 
    | 
    | 
    | 
    
   
  | 26 | 
    | 
    | 
    | 
    
   
  | 29 | 
    | 
    | 
    | 
    
   
  | 31 | 
    | 
    | 
    | 
    
   
  | 57 | 
    | 
    | 
    | 
    
  
 n= Number of animals per group; red bars indicate ages when animals from a
 particular group were scanned |