Temporal codes, timing nets, and music perception

Temporal codes and neural temporal processing architectures (neural timing nets) that potentially subserve perception of pitch and rhythm are discussed. We address 1) properties of neural interspike interval representations that may underlie basic aspects of musical tonality (e.g. octave similarities), 2) implementation of pattern-similarity comparisons between interval representations using feedforward timing nets, and 3) representation of rhythmic patterns in recurrent timing nets. Computer simulated interval-patterns produced by harmonic complex tones whose fundamentals are related through simple ratios showed higher correlations than for more complex ratios. Similarities between interval-patterns produced by notes and chords resemble similarity-judgements made by human listeners in probe tone studies. Feedforward timing nets extract common temporal patterns from their inputs, so as to extract common pitch irrespective of timbre and vice versa. Recurrent timing nets build up complex temporal expectations over time through repetition, providing a means of representing rhythmic patterns. They constitute alternatives to oscillators and clocks, with which they share many common functional properties.