Next, {HEAD ~ cells} are inoculated with {TAIL ~ neurotropic virus} under conditions that restrict viral propagation 
are inoculated with
Next , { HEAD ~ cells } are inoculated with { TAIL ~ neurotropic virus } under conditions that restrict viral propagation
OTH OTH HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH