Fig 5. Comparing LS with SC.

(A) From left to right: the AN population response for a harmonic complex with the 1^st – 4^th harmonics. The y-axis is the CFs normalized by the fundamental frequency, in a linear scale (f₀ = 240 Hz). The x-axis indicates the post-stimulus time (between 10ms to 15ms). Next, the h coefficient vectors for the LS case (λ = 0.0) and for the sparse case (λ = 0.01). (B) Same as in (A) but for a complex tone stimulus that contains the harmonics 10^th–13^th. Note that for the lower harmonic stimulus (A), the results between the two cases, i.e., h_LS vs. h_SC, are almost identical. On the other hand, for the stimuli with the higher harmonics (B), the difference is more substantial. Specifically, there are much more nonzero coefficients in h_LS than in h_SC that are unrelated to the original spectrum structure of the signal (compare with the FTs in Fig 2A).