Transistors 51 and 52 are for transferring {TAIL ~ voltage} to {HEAD ~ the selecting gate lines} SGDI 
Transistors 51 and 52 are for transferring { TAIL ~ voltage } to { HEAD ~ the selecting gate lines } SGDI
OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH