Figure 7.

Delayed feedforward inhibition regulates the development of orientation and direction selectivities. A, Percentage changes in the integrated total input to the centered TN in each direction through training in the simulation (average of 5 trials ± SEM) in the cases of a normalized inhibitory amplitude = 0 (top left), 0.5 (top right), 1 (bottom left), and 1.5 (bottom right). The normalized inhibitory amplitude is the scale factor of synaptic strengths from the INs to the TNs. The above conditions in Figures 1–5 correspond to the case of the normalized inhibitory amplitude = 1.0. B, Direction (solid line) and orientation (dashed line) indices of the integrated total inputs against the normalized inhibitory amplitude (average of 5 trials ± SEM). C, Time profiles of the firing rate of the centered TN in the cases of the normalized inhibitory amplitude = 0 (dotted line), 0.5 (dashed line), 1 (solid line), and 1.5 (dotted-dashed line). D, Averaged changes in the synaptic strengths in the horizontal orientations against the trained direction (one trial). The line types correspond to those in C.