FIG. 3.

The saccade generator. A. The premotor network. The excitatory burst neurons (EBN) and inhibitory burst neurons (IBN) send local feedback projections that implement reciprocal inhibition for generating accurate and high-velocity saccades. OPN, omnipause neurons; yellow box: feedback gain. B. The model burst neuron membrane. The short latency negative feedback loop is schematized as a blue arrow with a yellow box. This loop is around a high-gain (k) amplifier built into the burst neurons. Although the gain of the negative feedback loop around the burst neuron circuit determines the amplitude of the saccade, the delay time is not the main determinant of the frequency of saccadic oscillations. (Red lines indicate inhibitory projections. Green lines indicate excitatory projections. The blue line indicates feedback projection.)