Target azimuth tuning functions under altered binaural cue conditions. A, C, E, G: target azimuth tuning functions of 4 neurons for single sources under 3 binaural cue conditions: standard (solid line), ITD only (dashed line; only ITD varies), and fixed ITD (dotted line; ITD fixed to zero). Frequency value in each panel indicates the neuron's BF. B, D, F, H: target azimuth tuning functions in the presence of a central interferer (arrowheads) for the neurons with corresponding single-source tuning functions in panel at left.