Recent studies show that the classical model based on axonal delay-lines may not explain the human spatial coding based on interaural time differences (ITD). Instead, a population-code model called “opponent channels” is suggested. Event-related potentials (ERPs) to ITD-changes are used to test the predictions of this model by considering the sounds before and after the change as adapter and probe stimuli, respectively. It is assumed that the former stimulus causes adaptation of the neurons with selectivity to its side, and that the ERP N1/P2 complex to the ITD-change is the specific response of the neurons with selectivity to the side of the probe sound. However, the ERP N1/P2 to ITD-shifts is a global (non-specific) acoustic change complex of cortical origin evoked by any abrupt change in the auditory environment. It probably does not reflect the activity of some stimulus-specific neuronal units that have escaped the refractory effect of the preceding adapter, which means violation of the crucial assumption in an adapter-probe paradigm. We recorded the ERPs to lateral shifts of click trains produced by switching their ITDs between various initial and target ITDs within the physiological range of -600 to +600 us. The relationship between N1/P2 magnitude and the direction and range of ITD-shift did not comply with additivity of probe responses presumed in adapter-probe paradigms, casting doubt on the tests of opponent channels model based on ERPs to abrupt ITD-changes.