Synesthesia in children: association of colors with pure tone frequencies.
Explore the source record for details and available documents.
SEARCH · Search PubMed
Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
This paper is concerned with the lower limit of pitch for complex, harmonic sounds, like the notes produced by low-pitched musical instruments. The lower limit of pitch is investigated by measuring rate discrimination thresholds for harmonic tones filtered into 1.2-kHz-wide bands with a lower cutoff frequency, F(c), ranging from 0.2 to 6.4 kHz. When F(c) is below 1 kHz and the harmonics are in cosine phase, rate discrimination threshold exhibits a rapid, tenfold decrease as the repetition rate is increased from 16 to 64 Hz, and over this range, the perceptual quality of the stimuli changes from flutter to pitch. When F(c) is increased above 1 kHz, the slope of the transition from high to low thresholds becomes shallower and occurs at progressively higher rates. A quantitative comparison of the cosine-phase thresholds with subjective estimates of the existence region of pitch from the literature shows that the transition in rate discrimination occurs at approximately the same rate as the lower limit of pitch. The rate discrimination experiment was then repeated with alternating-phase harmonic tones whose envelopes repeat at twice the repetition rate of the waveform. In this case, when F(c) is below 1 kHz, the transition in rate discrimination is shifted downward by almost an octave relative to the transition in the cosine-phase thresholds. The results support the hypothesis that in the low-frequency region, the pitch limit is determined by a temporal mechanism, which analyzes time intervals between peaks in the neural activity pattern. It seems that temporal processing of pitch is limited to time intervals less than 33 ms, corresponding to a pitch limit of about 30 Hz.
Explore the source record for details and available documents.
The effect of the filter bank on fundamental frequency (F0) discrimination was examined in four Nucleus CI24 cochlear implant subjects for synthetic stylized vowel-like stimuli. The four tested filter banks differed in cutoff frequencies, amount of overlap between filters, and shape of the filters. To assess the effects of temporal pitch cues on F0 discrimination, temporal fluctuations were removed above 10 Hz in one condition and above 200 Hz in another. Results indicate that F0 discrimination based upon place pitch cues is possible, but just-noticeable differences exceed 1 octave or more depending on the filter bank used. Increasing the frequency resolution in the F0 range improves the F0 discrimination based upon place pitch cues. The results of F0 discrimination based upon place pitch agree with a model that compares the centroids of the electrical excitation pattern. The addition of temporal fluctuations up to 200 Hz significantly improves F0 discrimination. Just-noticeable differences using both place and temporal pitch cues range from 6% to 60%. Filter banks that do not resolve the higher harmonics provided the best temporal pitch cues, because temporal pitch cues are clearest when the fluctuation on all channels is at F0 and preferably in phase.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Absolute pitch is a special ability which allows for special perceptual/cognitive strategies. Studies have shown differences in event-related scalp potentials between absolute-pitch (AP) and relative-pitch (RP) subjects of equal musical training. In this study, highly trained musicians (15 females/15 males) performed a melodic interval discrimination task, using intervals on-pitch in equal-tempered tuning (A4 = 440 Hz) and tuned a half-semitone sharp. Subjects identified target intervals (probability 0.2) in a series of 400 randomly transposed intervals. AP subjects were expected to perform differently across intonation conditions, whereas RP subjects were not. Event-related potentials (ERPs) were recorded from three midline sites and two lateral sites. ERPs were analyzed by principal component analysis of variance. Sex was also considered as an independent subject variable. Performance was not significantly different either by absolute pitch or sex. Reaction times did not reveal any significant interactions involving AP or sex, but showed a significant effect by response type (target/nontarget). Strong P3 activity appeared to the target melodic intervals regardless of subject group or intonation. PCA factors with maxima at 352, 511, and 709 ms were sensitive to task relevance. Males showed greater positivity than females along the midline. A significant intonation by response type by sex interaction indicated a greater spread of values for females than males, and greater similarity in response by sex for the sharp than the on-pitch intervals. AP subjects showed reduced P3 activity along the midline, but increased over lateral sites. In a difficult musical task, the ERPs were sensitive to the sex of the listeners, as well as to whether they had absolute pitch.
Both place and temporal codes in the peripheral auditory system contain pitch information, however, their actual use by the brain is unclear. Here pitch data are reported from users of the cochlear implant, which provides the ability to change the temporal code independently from the place code. With fixed electrode stimulation, both frequency discrimination and pitch estimate data show that the cochlear implant users can only discern differences in pitch for frequencies up to about 300 Hz. An integration model can predict pitch estimation from frequency discrimination, reinforcing Fechner's hypothesis relating sensation magnitude to stimulus discriminability. The present results suggest that 300 Hz is the upper boundary of the temporal code and that the absolute place information should be included in the present pitch models. They further suggest that future cochlear implants need to increase the number of independent electrodes to restore normal pitch range and resolution.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.