Network model for visually mediated ciliary locomotion. A: The model had six cells: LB, lateral B-type photoreceptor; Ib, Ie, Ii and IIIi, interneurons; VP1, ciliary motor neuron. The cells were Hodgkin-Huxley-like neurons. Membrane conductances also included noise. The match between empirical data and model properties was qualitative. For example, all synaptic connections were modeled as monosynaptic, which reflected ‘functional’ connections. The circuit was implemented in SNNAP . B1: The model responded to light, which was simulated by depolarizing LB, with increased VP1 activity. B2: The mean (+/- SD; n = 7) spiking frequency (Hz) of each cell before (dark) and during the light stimulus (light). Noise produced variability among simulations. In some cases, the error bars were not visible.