Figure 1.
Spectro-temporal aspect of timbre.
(a) Four frequencies were mixed with phase modulation. Zero (red, left panels in b–e) or π (blue, right panels in b–e) phasing was only applied to two higher frequencies (f2 and f3). (b), (c) Waveforms and Fourier analysis of two tones applied with phasing; two tones have different envelopes with same frequency components. (d), (e) Modulation by clipping the amplitude to the magnitude of a single tone. Two mixtures have similar envelopes but different frequency distribution.
Table 1.
Correlations between Score, Click, and Response Time.
Table 2.
Descriptive Statistics of Score, Response Time, Click, Same and Different Score.
Figure 2.
Equivalent current dipoles of the auditory brain response.
(a) Coronal, (b) sagittal, and (c) axial views of the dipole localization rendered on TR images of a subject. The blue dot indicates the M100 dipole, while the red rectangle indicates the M50 dipole. The locations of the two dipoles are localized in the primary auditory cortex. (d) Source waveform of M50 and M100 dipoles. The waveforms of the M100 (in the upper), M50 (in the middle) dipoles, and goodness-of-fit of the two dipoles (in the bottom). A left vertical line indicates the stimulus onset time (t0), whereas a right vertical line corresponds to the time at which M50 dipole is fitted. The topographies of the magnetic fields of (e) M50 and (f) M100. The locations of two dipoles of M50 and M100 are similar, although the orientations of two dipoles are the opposite.
Figure 3.
Comparison of the dipole strengths.
(a) Response suppression. Dipole strengths of the responses to S1 (yellow) vs. S2 (bright green). N = 35 (subjects)×2 (sessions)×2 (conditions). (b) Dipole strengths of the S1 responses to S1 stimuli of 0 phase modulation vs. π. Dipole strengths of 0 phase (magenta) is significantly higher than those of π phase (cyan). N = 35 (subjects)×2 (sessions). (c) Dipole strengths of the S2 responses to S1 stimuli of 0 phase modulation vs. π. Only M100s of the left hemisphere were significantly different. N = 35 (subjects)×2 (sessions). (d) Dipole strengths of the S2 responses to stimuli in same pairs vs. different. In the right hemisphere, M50 and M100 in different conditions were significantly higher than those in the same condition. N = 35 (subjects)×2 (sessions). For all, the error bar indicates standard error of mean (SEM). All values are logarithmically transformed. N: number of independent data points. *: significant at the 0.05 level, **: significant at the 0.01 level, ***: significant at the 0.001 level, n.s.: not significant.
Table 3.
Auditory M50/M100 Responses to S1.
Table 4.
Auditory M50/M100 Responses to S2.
Table 5.
Effect by presenting order and condition: Gating in and out effect.
Figure 4.
Schematic diagram of Experimental Procedure.
(a) Auditory stimuli were presented as a pair with 5.5–6.5 s (mean, 6 s). A pair consists of two identical tones (same pairs) or two different tones in timbre (different pairs). Participants were asked to detect the different pairs. (b) Two consecutive tones were separated with 500 ms intervals. (c) Each session was comprised of 50 same pairs and 50 different pairs. Two sessions were counterbalanced by interchanging the S1 stimulus.