“…Although it is possible that these GABAergic inputs to RBCs are mediated by amacrine cells that are activated purely by ON or OFF channels, combinations of ON and OFF inputs cannot be ruled out (Werblin and Dowling, 1969; Dacheux and Raviola, 1995; Bloomfield and Volgyi, 2007). Previous work on amacrine cells that respond to both light increments and decrements has shown that these cells can mediate feedforward inhibition to ganglion cells (Cook and Werblin, 1994; Taylor, 1999) or feedback inhibition onto bipolar cells (Shields and Lukasiewicz, 2003) and possess a similar sensitivity to TTX (Miller and Dacheux, 1976; Werblin, 1977; Cook and Werblin, 1994; Miller et al, 2006; Bloomfield and Volgyi, 2007), as observed here (Figure 3). …”