Simulation model for interaural time difference discrimination for tones

Difference limens for the interaural time difference (ITD) can be measured with a 2-interval, 2-alternative forced-choice staircase using the ITD as the staircase variable. Experimental results can be predicted by a computational model that simulates the experiment protocol in every important detail, as applied to human listeners, but the computer can tolerate hundreds of times more runs. At the core of the simulation is a decision process based on an opponency model for the two medial superior olives (MSO). MSO firing rates as functions of ITD are initially determined by a stochastically driven Hodgkin-Huxley cell model and represented in the simulation by a four-parameter fitted function. A corresponding noise function is estimated from multiple runs of the cell model. Left-right symmetry in both the model and the experiment protocol simplifies the calculations. Simulations have practical value in relating staircase thresholds to the underlying parameterized firing rate functions for given staircase var...