Xindong SONG - Academia.edu (original) (raw)

Papers by Xindong SONG

The mechanisms of pitch perception have been one of auditory neuroscience’s central questions for... more The mechanisms of pitch perception have been one of auditory neuroscience’s central questions for over a century due to the importance of pitch in music and speech perception. Yet the evolutionary origins of pitch perception, and whether its underlying mechanisms are unique to humans, is unknown. For my dissertation, I have investigated the perceptual properties of pitch in marmoset monkeys. One of the most well-known phenomena of pitch perception, that of the missing fundamental, has suggested that humans do not simply use the fundamental frequency component to perceive pitch from harmonic complex sounds but can actively infer the pitch from the higher overtones or harmonics. It has been suggested that several non-human species are also sensitive to the pitch of missing fundamental sounds. However, none of these demonstrations has shown this sensitivity to pitch with a precision below three semitones. For humans to perceive Western music melodies, a precision of at least one semito...

Nature Communications

The primate cerebral cortex is organized into specialized areas representing different modalities... more The primate cerebral cortex is organized into specialized areas representing different modalities and functions along a continuous surface. The functional maps across the cortex, however, are often investigated a single modality at a time (e.g., audition or vision). To advance our understanding of the complex landscape of primate cortical functions, here we develop a polarization-gated wide-field optical imaging method for measuring cortical functions through the un-thinned intact skull in awake marmoset monkeys (Callithrix jacchus), a primate species featuring a smooth cortex. Using this method, adjacent auditory, visual, and somatosensory cortices are noninvasively parcellated in individual subjects with detailed tonotopy, retinotopy, and somatotopy. An additional pure-tone-responsive tonotopic gradient is discovered in auditory cortex and a face-patch sensitive to motion in the lower-center visual field is localized near an auditory region representing frequencies of conspecific ...

Light: Science & Applications

Two-photon laser-scanning microscopy has become an essential tool for imaging neuronal functions ... more Two-photon laser-scanning microscopy has become an essential tool for imaging neuronal functions in vivo and has been applied to different parts of the neural system, including the auditory system. However, many components of a two-photon microscope, such as galvanometer-based laser scanners, generate mechanical vibrations and thus acoustic artifacts, making it difficult to interpret auditory responses from recorded neurons. Here, we report the development of a silent two-photon imaging system and its applications in the common marmoset (Callithrix Jacchus), a non-human primate species sharing a similar hearing range with humans. By utilizing an orthogonal pair of acousto-optical deflectors (AODs), full-frame raster scanning at video rate was achieved without introducing mechanical vibrations. Imaging depth can be optically controlled by adjusting the chirping speed on the AODs without any mechanical motion along the Z-axis. Furthermore, all other sound-generating components of the ...

ABSTRACTThe primate cerebral cortex is organized into specialized areas representing different fu... more ABSTRACTThe primate cerebral cortex is organized into specialized areas representing different functional modalities (e.g., vision, audition, touch) and their associations along a continuous surface. The functional maps of these areas, however, are often investigated in a single modality at a time. Here, we developed and applied to awake primates a polarization-enhanced wide-field optical imaging method for measuring cortical hemodynamics through the intact skull. Adjacent somatosensory, auditory, and visual cortices were noninvasively localized and rapidly parcellated in awake marmosets (Callithrix jacchus), a primate model featuring a smooth cortex. Detailed somatotopy, tonotopy, and retinotopy were also mapped out on an individual-subject basis, with a new pure-tone-responsive tonotopic gradient discovered outside the auditory core. Moreover, the motion-sensitive extent surrounding the primate-specific MT/V5 and the location of a face-sensitive patch were both revealed with respe...

The Journal of the Acoustical Society of America, 2019

The perception of the pitch of harmonic complex sounds is a crucial function of human audition, e... more The perception of the pitch of harmonic complex sounds is a crucial function of human audition, especially in music and speech processing. Whether the underlying mechanisms of pitch perception are unique to humans, however, is unknown. Based on estimates of frequency resolution at the level of the auditory periphery, psychoacoustic studies in humans have revealed several primary features of central pitch mechanisms. It has been shown that (1) the pitch strength of a harmonic tone is dominated by resolved harmonics; (2) pitch of resolved harmonics is sensitive to the quality of spectral harmonicity; and (3) pitch of unresolved harmonics is sensitive to the salience of temporal envelope cues. Here, we show that, for a standard musical tuning fundamental frequency of 440 Hz (ISO 16), the common marmoset (Callithrix jacchus), a New World monkey with a hearing range similar to that of humans, exhibits all the primary features of central pitch mechanisms demonstrated in humans. Thus, marmosets and humans may share similar pitch perception mechanisms, combined with previous findings of a specialized pitch processing region in both marmoset and human auditory cortex, suggesting that these mechanisms may have emerged early in primate evolution.

Hearing Research, 2016

The common marmoset (Callithrix jacchus) is a highly vocal New World primate species that has eme... more The common marmoset (Callithrix jacchus) is a highly vocal New World primate species that has emerged in recent years as a promising model system for studies of auditory and vocal processing. Our recent studies have examined perceptual mechanisms related to the pitch of harmonic complex tones in this species. However, no previous psychoacoustic work has measured marmosets' frequency discrimination abilities for pure tones across a broad frequency range. Here we systematically examined frequency difference limens (FDLs), which measure the minimum discriminable frequency difference between two pure tones, in marmosets across most of their hearing range. Results show that marmosets' FDLs are comparable to other New World primates, with lowest values in the frequency range of ~3.5-14 kHz. This region of lowest FDLs corresponds with the region of lowest hearing thresholds in this species measured in our previous study and also with the greatest concentration of spectral energy in the major types of marmoset vocalizations. These data suggest that frequency discrimination in the common marmoset may have evolved to match the hearing sensitivity and spectral characteristics of this species' vocalizations.

48th Midwest Symposium on Circuits and Systems, 2005., 2005

This paper describes the interface design for an in vitro neural biosensor which tends to combine... more This paper describes the interface design for an in vitro neural biosensor which tends to combine biological neural network and integrated circuits together in a microsystem for intelligent bio-computation. As a simple case, design and fabrication process for the 4×4 Microelectrode-Array (MEA) that interfaces neural tissue with circuits is presented in detail. The experimental results have primarily demonstrated good performance of the MEA that was fabricated in IC Manufacture Center for IME of Tsinghua University. A tentative 256×256 MEA containing two 128×128 MEAs (one for stimulation while the other for recording) for the final biosensor can hopefully arise from it by the same token. Additionally, we also briefly present the front-end design for the neural recording in this paper. I.

Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference, 2005

Multielectrode Arrays have currently been widely used as Neural-Network research tools. In this p... more Multielectrode Arrays have currently been widely used as Neural-Network research tools. In this paper, we propose a novel mixed integrated sensor array microsystem combining cultured biological neurons, silicon integrated circuits and optical components together on a single silicon substrate. Using the light emitting property of GaAs-LED dependent on current passing from the recorded action potentials signals by a Multielectrode-Array in situ, we are able to characterize the neural activities of the cultured neural networks directly with a visible image displayed by a monitoring CCD Camera. Researchers may use various ready image process tools for experimental data analysis to directly observe results.

Journal of Neuroscience, 2013

Pitch is one of the most fundamental percepts in the auditory system and can be extracted using e... more Pitch is one of the most fundamental percepts in the auditory system and can be extracted using either spectral or temporal information in an acoustic signal. Although pitch perception has been extensively studied in human subjects, it is far less clear how nonhuman primates perceive pitch. We have addressed this question in a series of behavioral studies in which marmosets, a vocal nonhuman primate species, were trained to discriminate complex harmonic tones differing in either spectral (fundamental frequency [f 0 ]) or temporal envelope (repetition rate) cues. We found that marmosets used temporal envelope information to discriminate pitch for acoustic stimuli with higher-order harmonics and lower f 0 values and spectral information for acoustic stimuli with lower-order harmonics and higher f 0 values. We further measured frequency resolution in marmosets using a psychophysical task in which pure tone thresholds were measured as a function of notched noise masker bandwidth. Results show that only the first four harmonics are resolved at low f 0 values and up to 16 harmonics are resolved at higher f 0 values. Resolvability in marmosets is different from that in humans, where the first five to nine harmonics are consistently resolved across most f 0 values, and is likely the result of a smaller marmoset cochlea. In sum, these results show that marmosets use two mechanisms to extract pitch (harmonic templates [spectral] for resolved harmonics, and envelope extraction [temporal] for unresolved harmonics) and that species differences in stimulus resolvability need to be taken into account when investigating and comparing mechanisms of pitch perception across animals.

Progress in Natural Science, 2009

The propagation of neuronal activities is a key feature to understanding information processing i... more The propagation of neuronal activities is a key feature to understanding information processing in networks. The analysis based on first-spikes of bursts in turn plays an important role in the research of neuronal activity propagation. Our focus here is to investigate how spatiotemporal patterns of neuronal first-spikes are affected by disinhibition. Multi-electrode arrays were used to record stimulationevoked bursts of multiple neurons in randomly cultured neuronal networks. Both the precise timing of and the rank relationships between first-spikes were analyzed. Compared with evoked bursts in the network's native state, the precise first-spike latencies in its disinhibited state are more consistent and the propagation of its bursting activities is much faster. Additional points of interest are that disinhibited neuronal networks can be evoked to generate stable and distinguishable neuronal first recruitment spatiotemporal patterns specific to the stimulation site, and that the disinhibition may cause the original spatiotemporal patterns to change in a heterogeneous manner with regards to different propagation pathways.

Biosensors and Bioelectronics, 2007

Microelectrode arrays (MEAs) provide a means to investigate the electrophysiological behavior of ... more Microelectrode arrays (MEAs) provide a means to investigate the electrophysiological behavior of neuronal systems through the measurements from neuronal culture preparations. Changes in activity patterns of neuronal networks are usually detected by applying neural chemicals. Because of the difficulties of fabricating the arrays, and the delicate and less reliable properties of cortical neurons, MEA-based systems with cortical neuronal networks for neurophamacological applications are technically difficult, therefore restricting their utility. Here, we report a new approach to the development of such MEA-based system with sensitive and durable MEAs conveniently fabricated and the culture conditions optimized. Upon growth differentiation, cortical neurons, cultured directly on MEAs, reach a developmentally stable and reliable activity state. With this system, we monitored the global spontaneous activities of neuronal networks and demonstrated the fine discrimination for specific substances and unique property of cortical neurons, which validated both the applicability and necessity of such system in pharmacological bioassay.

IEEE Transactions on Biomedical Engineering, 2009

In this paper, we study the spontaneous cortical neuronal network in hopes of finding a reliable ... more In this paper, we study the spontaneous cortical neuronal network in hopes of finding a reliable indicator of burst initiation pathway, which would allow us to study burst initiation in conjunction with burst propagation in future research. Electrical activity is recorded using a 96-electrode microelectrode array on a weekly batch culture (half of the medium was replaced twice every week). We hypothesize that the first-spike onset sequence, which we call first-spike rank order (FSRO) is a reliable indicator of burst initiation, and verified our hypothesis by studying evoked bursts using rearranged rank probability matrices. Under similar conditions, stimulating the same site reliably reproduces the same FSRO. Spontaneous bursts can be classified based on their FSRO using dendrogram clustering. Bursts with different first-spike sequences showed evidence of sharing common early-to-fire neurons, but early-to-fire neurons only consist of a minority of neuronal activity during burst initiation, which is in partial accordance with existing literature. In the study of early-to-fire neurons, we also noticed that our batch-cultured network did not show clear preburst activity, which may indicate fundamental difference compared to continuous perfusion culture.

Proceedings of the National Academy of Sciences, 2015

The perception of the pitch of harmonic complex sounds is a crucial function of human audition, e... more The perception of the pitch of harmonic complex sounds is a crucial function of human audition, especially in music and speech processing. Whether the underlying mechanisms of pitch perception are unique to humans, however, is unknown. Based on estimates of frequency resolution at the level of the auditory periphery, psychoacoustic studies in humans have revealed several primary features of central pitch mechanisms. It has been shown that (i) pitch strength of a harmonic tone is dominated by resolved harmonics; (ii) pitch of resolved harmonics is sensitive to the quality of spectral harmonicity; and (iii) pitch of unresolved harmonics is sensitive to the salience of temporal envelope cues. Here we show, for a standard musical tuning fundamental frequency of 440 Hz, that the common marmoset (Callithrix jacchus), a New World monkey with a hearing range similar to that of humans, exhibits all of the primary features of central pitch mechanisms demonstrated in humans. Thus, marmosets an...

The mechanisms of pitch perception have been one of auditory neuroscience’s central questions for... more The mechanisms of pitch perception have been one of auditory neuroscience’s central questions for over a century due to the importance of pitch in music and speech perception. Yet the evolutionary origins of pitch perception, and whether its underlying mechanisms are unique to humans, is unknown. For my dissertation, I have investigated the perceptual properties of pitch in marmoset monkeys. One of the most well-known phenomena of pitch perception, that of the missing fundamental, has suggested that humans do not simply use the fundamental frequency component to perceive pitch from harmonic complex sounds but can actively infer the pitch from the higher overtones or harmonics. It has been suggested that several non-human species are also sensitive to the pitch of missing fundamental sounds. However, none of these demonstrations has shown this sensitivity to pitch with a precision below three semitones. For humans to perceive Western music melodies, a precision of at least one semito...

Nature Communications

The primate cerebral cortex is organized into specialized areas representing different modalities... more The primate cerebral cortex is organized into specialized areas representing different modalities and functions along a continuous surface. The functional maps across the cortex, however, are often investigated a single modality at a time (e.g., audition or vision). To advance our understanding of the complex landscape of primate cortical functions, here we develop a polarization-gated wide-field optical imaging method for measuring cortical functions through the un-thinned intact skull in awake marmoset monkeys (Callithrix jacchus), a primate species featuring a smooth cortex. Using this method, adjacent auditory, visual, and somatosensory cortices are noninvasively parcellated in individual subjects with detailed tonotopy, retinotopy, and somatotopy. An additional pure-tone-responsive tonotopic gradient is discovered in auditory cortex and a face-patch sensitive to motion in the lower-center visual field is localized near an auditory region representing frequencies of conspecific ...

Light: Science & Applications

Two-photon laser-scanning microscopy has become an essential tool for imaging neuronal functions ... more Two-photon laser-scanning microscopy has become an essential tool for imaging neuronal functions in vivo and has been applied to different parts of the neural system, including the auditory system. However, many components of a two-photon microscope, such as galvanometer-based laser scanners, generate mechanical vibrations and thus acoustic artifacts, making it difficult to interpret auditory responses from recorded neurons. Here, we report the development of a silent two-photon imaging system and its applications in the common marmoset (Callithrix Jacchus), a non-human primate species sharing a similar hearing range with humans. By utilizing an orthogonal pair of acousto-optical deflectors (AODs), full-frame raster scanning at video rate was achieved without introducing mechanical vibrations. Imaging depth can be optically controlled by adjusting the chirping speed on the AODs without any mechanical motion along the Z-axis. Furthermore, all other sound-generating components of the ...

ABSTRACTThe primate cerebral cortex is organized into specialized areas representing different fu... more ABSTRACTThe primate cerebral cortex is organized into specialized areas representing different functional modalities (e.g., vision, audition, touch) and their associations along a continuous surface. The functional maps of these areas, however, are often investigated in a single modality at a time. Here, we developed and applied to awake primates a polarization-enhanced wide-field optical imaging method for measuring cortical hemodynamics through the intact skull. Adjacent somatosensory, auditory, and visual cortices were noninvasively localized and rapidly parcellated in awake marmosets (Callithrix jacchus), a primate model featuring a smooth cortex. Detailed somatotopy, tonotopy, and retinotopy were also mapped out on an individual-subject basis, with a new pure-tone-responsive tonotopic gradient discovered outside the auditory core. Moreover, the motion-sensitive extent surrounding the primate-specific MT/V5 and the location of a face-sensitive patch were both revealed with respe...

The Journal of the Acoustical Society of America, 2019

The perception of the pitch of harmonic complex sounds is a crucial function of human audition, e... more The perception of the pitch of harmonic complex sounds is a crucial function of human audition, especially in music and speech processing. Whether the underlying mechanisms of pitch perception are unique to humans, however, is unknown. Based on estimates of frequency resolution at the level of the auditory periphery, psychoacoustic studies in humans have revealed several primary features of central pitch mechanisms. It has been shown that (1) the pitch strength of a harmonic tone is dominated by resolved harmonics; (2) pitch of resolved harmonics is sensitive to the quality of spectral harmonicity; and (3) pitch of unresolved harmonics is sensitive to the salience of temporal envelope cues. Here, we show that, for a standard musical tuning fundamental frequency of 440 Hz (ISO 16), the common marmoset (Callithrix jacchus), a New World monkey with a hearing range similar to that of humans, exhibits all the primary features of central pitch mechanisms demonstrated in humans. Thus, marmosets and humans may share similar pitch perception mechanisms, combined with previous findings of a specialized pitch processing region in both marmoset and human auditory cortex, suggesting that these mechanisms may have emerged early in primate evolution.

Hearing Research, 2016

The common marmoset (Callithrix jacchus) is a highly vocal New World primate species that has eme... more The common marmoset (Callithrix jacchus) is a highly vocal New World primate species that has emerged in recent years as a promising model system for studies of auditory and vocal processing. Our recent studies have examined perceptual mechanisms related to the pitch of harmonic complex tones in this species. However, no previous psychoacoustic work has measured marmosets' frequency discrimination abilities for pure tones across a broad frequency range. Here we systematically examined frequency difference limens (FDLs), which measure the minimum discriminable frequency difference between two pure tones, in marmosets across most of their hearing range. Results show that marmosets' FDLs are comparable to other New World primates, with lowest values in the frequency range of ~3.5-14 kHz. This region of lowest FDLs corresponds with the region of lowest hearing thresholds in this species measured in our previous study and also with the greatest concentration of spectral energy in the major types of marmoset vocalizations. These data suggest that frequency discrimination in the common marmoset may have evolved to match the hearing sensitivity and spectral characteristics of this species' vocalizations.

48th Midwest Symposium on Circuits and Systems, 2005., 2005

This paper describes the interface design for an in vitro neural biosensor which tends to combine... more This paper describes the interface design for an in vitro neural biosensor which tends to combine biological neural network and integrated circuits together in a microsystem for intelligent bio-computation. As a simple case, design and fabrication process for the 4×4 Microelectrode-Array (MEA) that interfaces neural tissue with circuits is presented in detail. The experimental results have primarily demonstrated good performance of the MEA that was fabricated in IC Manufacture Center for IME of Tsinghua University. A tentative 256×256 MEA containing two 128×128 MEAs (one for stimulation while the other for recording) for the final biosensor can hopefully arise from it by the same token. Additionally, we also briefly present the front-end design for the neural recording in this paper. I.

Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference, 2005

Multielectrode Arrays have currently been widely used as Neural-Network research tools. In this p... more Multielectrode Arrays have currently been widely used as Neural-Network research tools. In this paper, we propose a novel mixed integrated sensor array microsystem combining cultured biological neurons, silicon integrated circuits and optical components together on a single silicon substrate. Using the light emitting property of GaAs-LED dependent on current passing from the recorded action potentials signals by a Multielectrode-Array in situ, we are able to characterize the neural activities of the cultured neural networks directly with a visible image displayed by a monitoring CCD Camera. Researchers may use various ready image process tools for experimental data analysis to directly observe results.

Journal of Neuroscience, 2013

Pitch is one of the most fundamental percepts in the auditory system and can be extracted using e... more Pitch is one of the most fundamental percepts in the auditory system and can be extracted using either spectral or temporal information in an acoustic signal. Although pitch perception has been extensively studied in human subjects, it is far less clear how nonhuman primates perceive pitch. We have addressed this question in a series of behavioral studies in which marmosets, a vocal nonhuman primate species, were trained to discriminate complex harmonic tones differing in either spectral (fundamental frequency [f 0 ]) or temporal envelope (repetition rate) cues. We found that marmosets used temporal envelope information to discriminate pitch for acoustic stimuli with higher-order harmonics and lower f 0 values and spectral information for acoustic stimuli with lower-order harmonics and higher f 0 values. We further measured frequency resolution in marmosets using a psychophysical task in which pure tone thresholds were measured as a function of notched noise masker bandwidth. Results show that only the first four harmonics are resolved at low f 0 values and up to 16 harmonics are resolved at higher f 0 values. Resolvability in marmosets is different from that in humans, where the first five to nine harmonics are consistently resolved across most f 0 values, and is likely the result of a smaller marmoset cochlea. In sum, these results show that marmosets use two mechanisms to extract pitch (harmonic templates [spectral] for resolved harmonics, and envelope extraction [temporal] for unresolved harmonics) and that species differences in stimulus resolvability need to be taken into account when investigating and comparing mechanisms of pitch perception across animals.

Progress in Natural Science, 2009

The propagation of neuronal activities is a key feature to understanding information processing i... more The propagation of neuronal activities is a key feature to understanding information processing in networks. The analysis based on first-spikes of bursts in turn plays an important role in the research of neuronal activity propagation. Our focus here is to investigate how spatiotemporal patterns of neuronal first-spikes are affected by disinhibition. Multi-electrode arrays were used to record stimulationevoked bursts of multiple neurons in randomly cultured neuronal networks. Both the precise timing of and the rank relationships between first-spikes were analyzed. Compared with evoked bursts in the network's native state, the precise first-spike latencies in its disinhibited state are more consistent and the propagation of its bursting activities is much faster. Additional points of interest are that disinhibited neuronal networks can be evoked to generate stable and distinguishable neuronal first recruitment spatiotemporal patterns specific to the stimulation site, and that the disinhibition may cause the original spatiotemporal patterns to change in a heterogeneous manner with regards to different propagation pathways.

Biosensors and Bioelectronics, 2007

Microelectrode arrays (MEAs) provide a means to investigate the electrophysiological behavior of ... more Microelectrode arrays (MEAs) provide a means to investigate the electrophysiological behavior of neuronal systems through the measurements from neuronal culture preparations. Changes in activity patterns of neuronal networks are usually detected by applying neural chemicals. Because of the difficulties of fabricating the arrays, and the delicate and less reliable properties of cortical neurons, MEA-based systems with cortical neuronal networks for neurophamacological applications are technically difficult, therefore restricting their utility. Here, we report a new approach to the development of such MEA-based system with sensitive and durable MEAs conveniently fabricated and the culture conditions optimized. Upon growth differentiation, cortical neurons, cultured directly on MEAs, reach a developmentally stable and reliable activity state. With this system, we monitored the global spontaneous activities of neuronal networks and demonstrated the fine discrimination for specific substances and unique property of cortical neurons, which validated both the applicability and necessity of such system in pharmacological bioassay.

IEEE Transactions on Biomedical Engineering, 2009

In this paper, we study the spontaneous cortical neuronal network in hopes of finding a reliable ... more In this paper, we study the spontaneous cortical neuronal network in hopes of finding a reliable indicator of burst initiation pathway, which would allow us to study burst initiation in conjunction with burst propagation in future research. Electrical activity is recorded using a 96-electrode microelectrode array on a weekly batch culture (half of the medium was replaced twice every week). We hypothesize that the first-spike onset sequence, which we call first-spike rank order (FSRO) is a reliable indicator of burst initiation, and verified our hypothesis by studying evoked bursts using rearranged rank probability matrices. Under similar conditions, stimulating the same site reliably reproduces the same FSRO. Spontaneous bursts can be classified based on their FSRO using dendrogram clustering. Bursts with different first-spike sequences showed evidence of sharing common early-to-fire neurons, but early-to-fire neurons only consist of a minority of neuronal activity during burst initiation, which is in partial accordance with existing literature. In the study of early-to-fire neurons, we also noticed that our batch-cultured network did not show clear preburst activity, which may indicate fundamental difference compared to continuous perfusion culture.

Proceedings of the National Academy of Sciences, 2015

The perception of the pitch of harmonic complex sounds is a crucial function of human audition, e... more The perception of the pitch of harmonic complex sounds is a crucial function of human audition, especially in music and speech processing. Whether the underlying mechanisms of pitch perception are unique to humans, however, is unknown. Based on estimates of frequency resolution at the level of the auditory periphery, psychoacoustic studies in humans have revealed several primary features of central pitch mechanisms. It has been shown that (i) pitch strength of a harmonic tone is dominated by resolved harmonics; (ii) pitch of resolved harmonics is sensitive to the quality of spectral harmonicity; and (iii) pitch of unresolved harmonics is sensitive to the salience of temporal envelope cues. Here we show, for a standard musical tuning fundamental frequency of 440 Hz, that the common marmoset (Callithrix jacchus), a New World monkey with a hearing range similar to that of humans, exhibits all of the primary features of central pitch mechanisms demonstrated in humans. Thus, marmosets an...