text: To assess the gross loss of neurons from DRG following nerve 
  injury, we generated the AvilFlpO;Atf3CreERT2;RC::FLTG mouse 
  line in which na¨ıve and axotomized sensory neurons were 
  differentially labelled. In this mouse line, all neurons express 
  in the na¨ıve state and switch to 
  tdTomato (Flp-dependent) 
  expressing green fluorescent protein (GFP) upon axonal damage 
  and concurrent tamoxifen treatment (Flp- and Cre-dependent) 
  (Figs. 1A and B). Following pilot experiments to optimize 
  tamoxifen dosing regimen, this approach was both highly efficient 
  and specific (with the caveat that it was necessary to wait for 
  several days after nerve injury for Cre-induced GFP expression): 
  14 days after SNItrans surgery, GFP was expressed by 99.1 6 
  0.6% of Atf3-expressing ipsilateral L4 DRG neurons, while we 
  observed GFP in only 4.6 6 0.7% of contralateral DRG neurons 
  (Figs. S2A–D, http://links.lww.com/PAIN/C84). We then used 
  a stereological approach to quantify the total number of neurons 
  in L4 DRG ipsilateral to injury 1, 2, 4, and 8 weeks after SNItrans, as 
  to injury. One week after SNItrans, we 
  well as contralateral 