sentence: As has been theoretically described , direction opponent responses such as observed in Figure 2 arise from the computation derived from dendrites of LPTCs and their inputs where both inhibitory GABA and excitatory nAChR are present ( Brotz et al ., 2001 ; Sinakevitch and Strausfeld , 2004 ; Shinomiya et al ., 2019 ; Davis et al ., 2020 ) .