Figure 1.

Coincidence and anti-coincidence conceptual models for the creation of bandpass, short-pass, and long-pass DTNs. Four traces are shown above each stimulus (black bars). The top traces show the membrane potentials from the summation of synaptic inputs and, if suprathreshold, the spike output of the DTN. The second, third, and bottom traces represent hypothetical synaptic inputs to a DTN. Each model has two or three inputs illustrated as EPSPs or IPSPs: (1) onset-evoked EPSP (ON EPSP; second trace); (2) offset-evoked EPSP (OFF EPSP; third trace; coincidence detection model only); (3) onset-evoked IPSP (ON IPSP; bottom trace). In the coincidence detection model, the DTN spikes only when the ON EPSP coincides with the OFF EPSP. This occurs for the 5 ms stimulus but not for the 1 or 8 ms stimuli. For the 1 ms stimulus, the ON and OFF EPSPs are absent or weak. For the 8 ms stimulus, the ON and OFF EPSPs do not coincide and the ON EPSP is rendered subhreshold by the ON IPSP. In the anti-coincidence models, the DTN spikes only when the ON EPSP does not coincide with the sustained ON IPSP. In the short-pass anti-coincidence model, this occurs for the 1 ms stimulus but not for the 5 or 8 ms stimuli. For the long-pass anti-coincidence model, this occurs only for the 8 ms stimulus. In the long-pass model, the ON EPSP is sustained, whereas the ON IPSP adapts. Suprathreshold EPSPs are illustrated with gray shading. The OFF EPSP is absent in both anti-coincidence models (dashed lines). Models were adapted and modified from Fuzessery and Hall (1999), Faure et al. (2003), and Leary et al. (2008).