Sound localization and neurons

Our ability to locate the direction of a sound's source depends largely on differences in the time that it takes for the sound to arrive at each ear. These interaural time delays (ITDs) can be extremely small (about 10 microseconds; ref. 1 ), so this ability is widely assumed to reflect the combined activity of many neurons 2 , 3 . Fitzpatrick et al. 4 estimated the pooling of 40 thalamic neurons to give a resolution of 16 microseconds. Our results, generated by a more conventional method, suggest that human thresholds might be determined by substantially fewer cells.