Neurocomputing 38-40:1401-1407, 2001.

An interaural time difference map resulting from axonal selection through non-specific learning

C. Leibold, R. Kempter, H. Wagner, and J. L. van Hemmen

An orderly spatial representation of the azimuthal position of a sound source has been observed in many animals. Barn owls, e.g., derive the azimuth from a neuronal map of interaural time difference (ITD) with a temporal precision of a few microseconds. We present a model of how an ITD map can develop in an array of spiking neurons in the barn owl's nucleus laminaris . We have combined homosynaptic spike-based Hebbian learning with presynaptic propagation of synaptic modifications. The latter is a feasible interaction mechanism between neurons and may be orders of magnitude weaker than the former. It is a key to explaining the widely assumed place code proposed by Jeffress (1948).


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