Figure 7.

Models of the effect of GABA down-regulation on visual selectivity. (A) Down-regulation of GABA leads to impaired synapse elimination and decrease orientation selectivity. Depth of blue color of each neuron on the center indicates strength of its selectivity. With normal amount of GABA, selectivity becomes sharp with LTP/LTD mechanism. In contrast, with down-regulation of GABA, selectivity becomes less sharp. (B) Input from direction selective retinal ganglion cells (DSGCs) may provide stable direction selective input that is not affected by impaired synapse elimination during development. In contrast, orientation selectivity may be mainly formed from untuned inputs from LGN neurons and depends on normal synapse elimination.