Microsecond-precision sound localization emerges from slow equilibrium dynamics

Abstract

Precise sound localization relies on microsecond sensitivity to interaural time differences (ITDs), yet binaural perception exhibits sluggish tracking of dynamic acoustic cues. How microsecond-level ITD sensitivity arises despite such slow responses remains unresolved. This study proposes that ITD is represented as a stable equilibrium of neural population dynamics rather than through the classical place-coding framework based on delay-line coincidence detection. In this framework, excitatory and inhibitory interactions across frequency channels drive the system toward an equilibrium corresponding to the estimated ITD. Despite relying on relatively slow temporal dynamics, the model achieves microsecond-level precision and reproduces key physiological observations, including frequency-dependent best-delay distributions, without requiring explicit delay lines or precisely timed inhibition. These results challenge the classical place-coding framework and suggest a fundamentally different principle for binaural computation. More generally, the findings indicate that precise temporal information can emerge from stable dynamical states rather than from equally precise neural timing mechanisms, providing a potential resolution to a long-standing paradox in auditory neuroscience.