REPRESENTATION OF PITCH IN POPULATION-WIDE INTERSPIKE INTERVAL STATISTICS

Temporal coding of sensory information can arise through exogenous, stimulus-locked temporal patternings of spikes or through endogenous, stimulus-triggered temporal patterns of response [1, 2]. Phase-locking to stimulus waveforms permits strategies for stimulus localization that are based on temporal cross-correlation across sensory receptors and strategies for representation of form that are based on temporal autocorrelation within sensory channels. Phase-locked neural responses can be found in a variety of sensory modalities: audition, somatoception, vision (Fig. 1), proprioception (stretch receptors), and electroception. Figure 1. Phase-locking in a visual neuron. Responses of a typical lateral geniculate unit to a sinusoidal grating drifting at constant velocity. Period histograms (A,B) and all-order interval histograms (C,D) to resulting temporal modulations at 16 and 32 Hz. Spatial frequency rate tuning curve (E). Data courtesy of A. Prezybyszewski and D. Pollen [3]. In audition there is strong evidence that both localization and pitch perception utilize fine timing information provided by the phase-locking of auditory nerve fibers to acoustic stimuli. Our experimental work has focused on the early representation of pitch in the auditory pathway [4