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Auditory Tonotopic Map: Frequency-Place Population Coding

Interactive 3D model of a tonotopic neural population: each unit is tuned to a characteristic frequency arranged along a log-frequency place axis. Sweep a tone (or two), adjust level and tuning sharpness, and watch the activity peak — and its level-dependent broadening — move across the frequency map.

Medicine & Biophysics3DModerate60 FPS📱 Mobile-adapted⇄ 2D version

This simulator visualises the tonotopic principle that runs through the entire auditory system: neurons are arranged along an ordered, roughly log-frequency axis so that a sound's pitch is represented by the place of peak population activity rather than by any single cell's firing rate. A grid of instanced units, each with its own characteristic frequency and a Gaussian tuning curve in log-frequency space, lights up and rises in real time as you sweep a tone (or add a second, independent tone) across the audible range. Sound level and tuning sharpness controls reproduce two real, measurable effects — level-dependent broadening of frequency tuning, and the resolution limit that separates two close tones into one merged peak versus two distinct ones — while live readouts decode the stimulus frequency straight back out of the population response and report the error.

⚙ Under the hood

A 3D population of frequency-tuned neural units arranged along a log-frequency tonotopic axis lights up in response to one or two tones, showing how pitch is decoded from the place of peak activity and how level and tuning sharpness change how well close frequencies can be told apart.

hearingcochleatonotopic mapneurosciencepitch perceptionauditory cortex

3D · Three.js / WebGL renderer · 60 FPS target · runs fully client-side, no install