Indirect distributed inhibition model (IDI).

<p>A Sketch of the IDI model: The motion picture (V(i)) is the retinotopic visual input of the model having an amplitude proportional to stimulus velocity at each position. This motion picture (Profile 1) is the input of the (left) inhibitory and the (right) excitatory branch. For each position i, a velocity value V(i) is given. In the left branch the signal V(i) is spatially convolved with a rectangular lowpass filter kernel to lead to signal I(i). The signal I(i) is transformed by the synaptic transmission function syn_I() into the shunting signal sht(i). For each position i, the signal V(i) is shunted by sht(i) and, by the synaptical transmission function syn_v(), transformed into the conductances g_V(i). Profile 2 illustrates the motion picture after the presynaptic inhibition. In the final step, all conductances g_V(i) are used to calculate the output of the model. B Detailed sketch of the IDI model circuit. Retinotopic motion sensitive cells excite the inhibitory element of the circuit and the FD-cell. Before the motion sensitive elements reach the FD-cell, they are shunted in a spatially distributed way by the inhibitory element. The symbols of the different cells are explained at the bottom of the figure.