Pitch Coding Research Articles

Variations on E. Zwicker’s theme of frequency discrimination.

Eberhard Zwicker once suggested that human frequency discrimination was controlled by the apical cutoff of cochlear excitation rather than by the maximum of excitation [E. Zwicker and R. Feldtkeller, DasOhralsNachrichtenempfänger (Hirzel, Stuttgart, 1967)]. Physiological evidence supporting Zwicker’s suggestion has been obtained. Microelectrode recordings from the cochlear inner and outer hair cells have revealed that the sound frequency associated with their maximum excitation at a given cochlear location changes with SPL, whereas the subjective pitch remains nearly constant. In Mongolian gerbils, at the 2-kHz cochlear location, the frequency is lowered by about an octave when the SPL is increased from 20 to 80 dB [J. J. Zwislocki, Acta Otolaryngol. 111, 256–262 (1991)]. Over the same SPL range, the human pitch changes by only a few percent. A similar near invariance in the high-frequency cutoff of the hair-cell excitation has been found. As a result of the known spatial frequency mapping in the cochlea, this cutoff corresponds to the apical cutoff of hair-cell excitation. The results suggest that the cutoff rather than the excitation maximum constitutes the place code for pitch, especially since the excitation maximum is not sharp enough to account for the great sensitivity of humans and animals to frequency changes. This is consistent with Zwicker’s hypothesis. [Work supported by NIDCD.]

What Is the Cochlear Place Code for Pitch?

The advent of cochlear implants has increased the clinical interest in the cochlear code for pitch. It is widely believed that pitch is determined by the location of the excitation maximum in the cochlea. However, direct recordings from cochlear hair cells indicate that, for a given sound frequency, the location changes appreciably with sound intensity, whereas the corresponding pitch remains approximately constant. Correlated with this constancy is a surprising constancy of the location of the high-frequency cutoff of cochlear excitation.

メロディの符号化と再認

This experiment was attempted to investigate the strategies of pitch coding in melody processing. Twenty-six musically trained and twenty-six musically naive subjects were instructed to make recognition for melodies after a 12-s retention interval, during which four conditions of interference (i.e. pause, interfering melody, nonsense syllables, musical note names) were interpolated. Both the standard and comparison melodies were 6-tone sequences which composed of high-tonality structure or low-tonality structure. It was found that the recognition of musicians was severely disrupted by the "note names" under a tonal melody, while it was disrupted by "interfering melody" under an atonal melody. On the other hand, the recognition of non-musicians was significantly worse than musicians, and there were no significant differences in disruptive effects between the interferences. These findings suggest that musicians could used verbal (note names) coding strategy for tonal melody and sensory pitch coding strategies (ex. humming, whistling) for atonal melody, but that non-musicians could not use any effective strategies for melody coding. Results were also discussed in relation to contour and pitch of melodies.

Intact Absolute Pitch Ability After Left Temporal Lobectomy

A 17-year old pianist who possessed absolute pitch underwent an anterior left temporal lobectomy for the relief of intractable seizures. Prior to surgery he showed some fluctuation in the pattern of errors in notating single piano tones. Postoperatively he improved on this task, and one year later his performance was essentially perfect. On a short-term retention task given postoperatively he showed the expected effect of a left temporal-lobe and hippocampal lesion: he was impaired in the recall of a three-letter sequence after 18 sec with an interpolated verbal task. In contrast, retention of the names of three piano notes was excellent under the same conditions, as it is for control subjects with absolute pitch. The results are interpreted in terms of the dissociation between verbal mechanisms and those involved in the coding of pitch, and the seeming immunity of many musical abilities to the effects of left-hemisphere lesions.

Development of location-specific hair cell stereocilia in denervated embryonic ears.

The developmental mechanisms that allow physiological coding of acoustic pitch have remained unexplained. Cochlear hair cells that have different structures respond to different sound frequencies and synapse with neurons that project to different locations in the brain. How do these hair cells develop appropriate structures, and how are the connections between specific hair cells and the neurons that code for their pitch sensitivities matched? We have investigated one aspect of this by denervating embryonic chicken ears, before the time of hair cell production, and then transplanting them to the aneural chorioallantoic membrane of host embryos where they have continued to develop. We report that vestibular and auditory hair cell phenotypes differentiate appropriately and that correct gradients of hair cell structural phenotypes, as expressed in stereocilia bundles, develop in the cochleae of these denervated ears. Therefore, the normal development of gradients in hair cell stereocilia properties must be controlled by location-specific cues originating in the ear itself. Neuronally directed modification of target cell phenotypes is not required for the quite specific phenotype development represented by the stereocilia bundles of individual hair cells and the connectional matching in the numerous distinct peripheral information lines of the auditory system.

Neural temporal coding of low pitch. I. Human frequency-following responses to complex tones

The neural basis of low pitch was investigated in the present study by recording a brainstem potential from the scalp of human subjects during presentation of complex tones which evoke a variable sensation of pitch. The potential recorded, the frequency-following response (FFR), reflects the temporal discharge activity of auditory neurons in the upper brainstem pathway. It was used as an index of neural periodicity in order to determine the extent to which the low pitch of complex tones is encoded in the temporal discharge activity of auditory brainstem neurons. A tone composed of harmonics of a common fundamental produces a sensation of pitch equal to that of the ‘missing’ fundamental. Such signals generate brainstem potentials which are spectrally similar to FFR recorded in response to sinusoidal signals equal in frequency to the missing fundamental. Both types of signals generate FFR which are periodic, with a frequency similar to the perceived pitch of the stimuli. It is shown that the FFR to the missing fundamental is not the result of a distortion product by recording FFR to a complex signal in the presence of low-frequency bandpass noise. Neither is the FFR the result of neural synchronization to the waveform envelope modulation pattern. This was determined by recording FFR to inharmonic and quasi-frequency-modulated signals. It was also determined that the ‘existence region’ for FFR to the missing fundamental lies below 2 kHz and that the most favorable spectral region for FFR to complex tones is between 0.5 and 1.0 kHz. These results are consistent with the hypothesis that far-field-recorded FFR does reflect neural activity germane to the processing of low pitch and that such pitch-relevant activity is based on the temporal discharge patterns of neurons in the upper auditory brainstem pathway.

Hands-on musical acoustics in the elementary classroom

The author has developed a minicourse for school teachers on how they can include acoustics in their teaching of science, with particular emphasis on musical sounds. The organizing theme is the direct, hands-on accessibility of many basic ideas in this area. The course is divided into three units: (1) simple vibrators, covering ideas about pitch, frequency, mass, and stiffness; (2) vibrators with several natural frequencies, presenting concepts of standing waves, nodes, and techniques for manipulating the sounds from such a vibrator; and (3) sound waves themselves, with emphasis on the wind instruments. An important part of each unit is the “dessert”—a simple musical toy whose operation illustrates the ideas discussed: (1) a seven-note, pentatonic thumb harp (African sansa or kalimba) constructed from materials indigenous to the American shopping center; (2) a tromba marina (bowed monochord), also built from cheap, readily available materials; and (3) a “flugle”—a closed/open cylindrical whistle on which bugle calls can be played. A color code for pitch makes it easy for beginners to play familiar tunes.

High-freqeuncy pitch perception

The alleged absence of musical pitch information for pure-tone frequencies above about 5 kHz is often cited as constituting evidence for temporal coding of pure-tone pitch below 5 kHz. However, the experimental data on which this allegation is based are both meager and equivocal. In this study, pure-tone pitch perception for frequencies above 10 kHz was investigated using three paradigms: open set melody recognition by naive observers, and melodic dictation and musical interval adjustment by musicians. The results indicate that significant musical-pitch information is available for frequencies above 10 kHz, although it is severely degraded relative to information at low frequencies. We have also investigated another pitch phenomenon which is assumed to be temporally based, the pitch differences associated with amplitude differences between the two components of unresolved two-component complex tones. This pitch information is also significant, but degraded, for frequencies above 10 kHz. The degree of degradation of both types of pitch information at high frequencies is consistent with the relative increase in pure-tone frequency DL's at high frequencies and is thus not incompatible with certain temporal models. [Supported by NINCDS.]

Pitch of narrow-band signals.

This study investigated the pitch elicited by complex narrow bandwidth signals. These signals ranged from two-component tones to multiple-component approximations of narrow-band noise. All were contained within 10-, 20-, or 50-Hz bandwidths. Listeners were asked to adjust the frequency of a pure tone to match the pitch they heard in a given complex signal. A simple model suggests that the pitch of these complex signals should match that of a pure tone set to the center frequency. For a majority of the signals, the performance of three of our four listeners was not different from the model predictions. However, the two-component signals were apparently resolved and two simultaneous pitches were heard by some listeners. Our fourth listener heard two sequential pitches in many of the complex signals. We are unable to account for that performance although the pitch matches were very repeatable. These results have implications for an understanding of pitch coding and auditory spectral resolution.

Pure-tone anomalies. I. Pitch-intensity effects and diplacusis in normal ears.

Pitch-intensity functions were obtained in both ears of five normal-hearing subjects, together with measurements of binaural diplacusis as a function of intensity. The results show that pitch-intensity functions are often significantly different in the two ears of a given subject at a given frequency. Furthermore, for each subject and frequency condition tested, an intensity existed for which no significant diplacusis was found. For these conditions, therefore, binaural diplacusis as a function of intensity could be accounted for by the interaural differences in pitch-intensity functions. Forward-masking patterns (FMP's) as a function of intensity were also obtained in both ears of several subjects. The FMP's were compared with pitch-intensity functions, obtained for the same conditions, for evidence of a covariation in the direction of shifts in masking patterns as a function of intensity with the direction of pitch shifts as a function of intensity. No convincing evidence of such a covariation was found. The implications of the results of these experiments are discussed relative to the question of temporal versus tonotopic coding of pure-tone pitch.

Macrophage infiltration of breast tumours: a prospective study.

In 50 cases of infiltrating breast cancer investigated in a prospective study the number of macrophages within each tumour was assessed. The macrophages were identified by their cytoplasmic acid phosphatase activity. The number of lymphocytes and plasma cells within the tumours were graded by a scoring technique. Significantly fewer cases with metastases were found among those with high macrophage and plasma cell scores. There was no correlation between lymphoreticular infiltration and the degree of tumour differentiation, but in cases without metastases the lymphoreticular infiltration between tumour cells was nearly always only slight when the macrophage score was low.

Temporal Integration at 125 Hz

An apparent lack of temporal integration for a 125-Hz signal was interpreted as having implications for the neural coding of periodicity pitch by Campbell and Counter [J. Acoust. Soc. Amer 45, 691–693 (1969)]. Watson and Gengel [J. Acoust. Soc. Amer. 46, 989–997 (1969)] suggested, rather, that the failure to observe temporal integration at 125 Hz was due to the spread of energy at the shorter durations upward into frequency regions of greater sensitivity. Consideration of the data mentioned above and additional data gathered at 125 Hz with durations of 30, 100, and 300 msec and rise/fall times of 1 and 5 msec presented with and without a noise (160 to 360 Hz), intended to minimize the upward spread of energy, indicate that the apparent lack of integration was due to the upward spread of energy. The rise/fall time does, however, seem to play a crucial role in this upward spread of energy rather than the short durations, per se. Furthermore, for higher frequencies, rise/fall times do not seem as critical.

Stimulus coding by medial superior olivary neurons.

Stimulus coding by medial superior olivary neurons.G Moushegian, A L Rupert, and T L LangfordG Moushegian, A L Rupert, and T L LangfordPublished Online:01 Sep 1967https://doi.org/10.1152/jn.1967.30.5.1239MoreSectionsPDF (3 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Previous Back to Top Download PDF FiguresReferencesRelatedInformation Cited ByEntracking as a Brain Stem Code for Pitch: The Butte Hypothesis15 April 2016Phase-Locked Responses to Pure Tones in the Inferior ColliculusLiang-Fa Liu, Alan R. Palmer, and Mark N. Wallace1 March 2006 | Journal of Neurophysiology, Vol. 95, No. 3Physiological Studies of the Precedence Effect in the Inferior Colliculus of the Cat. II. Neural MechanismsRuth Y. Litovsky, and Tom C. T. Yin1 September 1998 | Journal of Neurophysiology, Vol. 80, No. 3Effects of superior olivary complex lesions on binaural responses in rat auditory cortexBrain Research, Vol. 605, No. 2Responses elicited from medial superior olivary neurons by stimuli associated with binaural masking and unmaskingHearing Research, Vol. 15, No. 1Transmission delay of phase-locked cells in the medial geniculate bodyHearing Research, Vol. 3, No. 1Phase-locked responses to low frequency tones in the medial geniculate bodyHearing Research, Vol. 1, No. 3Dendritic arrangements in the cat medial superior oliveNeuroscience, Vol. 2, No. 1The effect of sound pressure waveform on human brain stem auditory evoked responsesBrain Research, Vol. 92, No. 3Sound localization: the role of the commissural pathways of the auditory system of the catBrain Research, Vol. 82, No. 1Differential brainstem pathways for the conduction of auditory frequency-following responsesElectroencephalography and Clinical Neurophysiology, Vol. 36Responses of neurones in the rabbit inferior colliculus. II. Influence of binaural tonal stimulationBrain Research, Vol. 47, No. 1Responses of inferior colliculus neurons to free field auditory stimuliExperimental Neurology, Vol. 35, No. 3Receptor and neural responses in auditory masking of low frequency tonesElectroencephalography and Clinical Neurophysiology, Vol. 32, No. 1Unit responses from the nucleus angularis in the pigeon's medullaComparative Biochemistry and Physiology Part A: Physiology, Vol. 40, No. 2Neuronal responses of kangaroo rat ventral cochlear nucleus to low-frequency tonesExperimental Neurology, Vol. 26, No. 1Poststimulus-time response patterns in the nuclei of the cat superior olivary complexExperimental Neurology, Vol. 23, No. 2 More from this issue > Volume 30Issue 5September 1967Pages 1239-61 https://doi.org/10.1152/jn.1967.30.5.1239PubMed6055354History Published online 1 September 1967 Published in print 1 September 1967 Metrics

Phase-locked response to low-frequency tones in single auditory nerve fibers of the squirrel monkey.

Phase-locked response to low-frequency tones in single auditory nerve fibers of the squirrel monkey.