A, Five rods recorded in flat-mounted salamander retina with the multiple patch electrode recording system. B, Original locations of the five rods before recording. C, Voltage responses of Rod1,0; Rod0,−1; Rod−1,0; and Rod0,1 to a −1 nA current step (1 s) injected into Rod0,0. D, Same experiments as in C in the presence of 100 µM ZD7288. E, Average voltage responses of eight five-rod clusters to −1 nA current injection into the center rod. Rod−1,0/Rod1,0 and Rod0,1/Rod0,−1 are in two orthogonal directions. Error bars are standard deviations, and p values from t test indicate that there are no statistical significant differences between Rod−1,0 and Rod1,0 responses, between Rod0,1 and Rod0,−1 responses, and between the two orthogonal rod pairs.