Stimulus dependent neural correlation: an example from the cochlear nucleus.

Results of several recent cross-correlation studies have been interpreted in terms of "neuronal plasticity" and "stimulus dependent wiring diagrams" produced by presumed dynamic neural reorganization mechanisms. Presented here are examples of stimulus-dependent cross-correlograms observed in a pair of type IV units recorded in the dorsal cochlear nucleus (DCN). The interpretation of these correlation data is based on current hypotheses of DCN circuitry. It is suggested that plasticity mechanisms are not responsible for these stimulus-dependent correlations. A more likely mechanism is one that allows various portions of a hard wired neural circuit to be selectively activated by the stimuli.