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Combination of spectral and binaurally created harmonics in a common central pitch processor.

Gockel HE, Carlyon RP, Plack CJ - J. Assoc. Res. Otolaryngol. (2010)

Bottom Line: Component frequencies were chosen such that the relative pitch judgement revealed whether a residue pitch was heard or not.The results showed that listeners were equally likely to perceive a residue pitch when one component was dichotic and the other was spectral as when the components were both spectral or both dichotic.This suggests that there exists a single mechanism for the derivation of residue pitch from binaurally created components and from spectral components, and that this mechanism operates at or after the level of the dorsal nucleus of the lateral lemniscus (brainstem) or the inferior colliculus (midbrain), which receive inputs from the medial superior olive where temporal information from the two ears is first combined.

View Article: PubMed Central - PubMed

Affiliation: MRC Cognition and Brain Sciences Unit, 15 Chaucer Road, Cambridge, UK. hedwig.gockel@mrc-cbu.cam.ac.uk

ABSTRACT
A fundamental attribute of human hearing is the ability to extract a residue pitch from harmonic complex sounds such as those produced by musical instruments and the human voice. However, the neural mechanisms that underlie this processing are unclear, as are the locations of these mechanisms in the auditory pathway. The ability to extract a residue pitch corresponding to the fundamental frequency from individual harmonics, even when the fundamental component is absent, has been demonstrated separately for conventional pitches and for Huggins pitch (HP), a stimulus without monaural pitch information. HP is created by presenting the same wideband noise to both ears, except for a narrowband frequency region where the noise is decorrelated across the two ears. The present study investigated whether residue pitch can be derived by combining a component derived solely from binaural interaction (HP) with a spectral component for which no binaural processing is required. Fifteen listeners indicated which of two sequentially presented sounds was higher in pitch. Each sound consisted of two "harmonics," which independently could be either a spectral or a HP component. Component frequencies were chosen such that the relative pitch judgement revealed whether a residue pitch was heard or not. The results showed that listeners were equally likely to perceive a residue pitch when one component was dichotic and the other was spectral as when the components were both spectral or both dichotic. This suggests that there exists a single mechanism for the derivation of residue pitch from binaurally created components and from spectral components, and that this mechanism operates at or after the level of the dorsal nucleus of the lateral lemniscus (brainstem) or the inferior colliculus (midbrain), which receive inputs from the medial superior olive where temporal information from the two ears is first combined.

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Schematic diagram of pitch stimuli. A Single component stimuli that evoke a tonal percept when presented monaurally (top) and for which binaural presentation is necessary (bottom). B Stimuli with two harmonics used in the present experiment.
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Fig1: Schematic diagram of pitch stimuli. A Single component stimuli that evoke a tonal percept when presented monaurally (top) and for which binaural presentation is necessary (bottom). B Stimuli with two harmonics used in the present experiment.

Mentions: A tonal percept can be produced by a pure tone or a narrowband noise (NBN; see Fig. 1A, top). A pitch can also be produced by presenting a wideband noise diotically, i.e., the same white noise to both ears, except for a narrow frequency region in which the noise is decorrelated between the two ears (see Fig. 1A, bottom). For this “Huggins pitch” (HP) stimulus (Cramer and Huggins 1958), the stimulus presented to each ear alone sounds just like a white noise. However, when the stimulus is presented binaurally, the listener perceives not only a noise, coming from the center of the head, but also a faint tone with a pitch that corresponds to the center frequency of the narrow band that is interaurally decorrelated. The tonal percept is lateralized to one ear or the other in a way that varies idiosyncratically across listeners (Raatgever and Bilsen 1986; Zhang and Hartmann 2008). HP stimuli produce a clear musical pitch, supporting melody recognition (Akeroyd et al. 2001). In contrast to a pure tone or narrowband noise, for which pitch information is available monaurally at the level of the auditory nerve, the perception of HP depends on fine timing information from the two ears being combined, and thus, depends on central processing (beyond the cochlear nucleus). There is physiological evidence that this processing occurs in the medial superior olive (MSO), and that the results of this brainstem processing can be measured in the inferior colliculus (IC; Palmer and Shackleton 2002).FIG. 1


Combination of spectral and binaurally created harmonics in a common central pitch processor.

Gockel HE, Carlyon RP, Plack CJ - J. Assoc. Res. Otolaryngol. (2010)

Schematic diagram of pitch stimuli. A Single component stimuli that evoke a tonal percept when presented monaurally (top) and for which binaural presentation is necessary (bottom). B Stimuli with two harmonics used in the present experiment.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3046332&req=5

Fig1: Schematic diagram of pitch stimuli. A Single component stimuli that evoke a tonal percept when presented monaurally (top) and for which binaural presentation is necessary (bottom). B Stimuli with two harmonics used in the present experiment.
Mentions: A tonal percept can be produced by a pure tone or a narrowband noise (NBN; see Fig. 1A, top). A pitch can also be produced by presenting a wideband noise diotically, i.e., the same white noise to both ears, except for a narrow frequency region in which the noise is decorrelated between the two ears (see Fig. 1A, bottom). For this “Huggins pitch” (HP) stimulus (Cramer and Huggins 1958), the stimulus presented to each ear alone sounds just like a white noise. However, when the stimulus is presented binaurally, the listener perceives not only a noise, coming from the center of the head, but also a faint tone with a pitch that corresponds to the center frequency of the narrow band that is interaurally decorrelated. The tonal percept is lateralized to one ear or the other in a way that varies idiosyncratically across listeners (Raatgever and Bilsen 1986; Zhang and Hartmann 2008). HP stimuli produce a clear musical pitch, supporting melody recognition (Akeroyd et al. 2001). In contrast to a pure tone or narrowband noise, for which pitch information is available monaurally at the level of the auditory nerve, the perception of HP depends on fine timing information from the two ears being combined, and thus, depends on central processing (beyond the cochlear nucleus). There is physiological evidence that this processing occurs in the medial superior olive (MSO), and that the results of this brainstem processing can be measured in the inferior colliculus (IC; Palmer and Shackleton 2002).FIG. 1

Bottom Line: Component frequencies were chosen such that the relative pitch judgement revealed whether a residue pitch was heard or not.The results showed that listeners were equally likely to perceive a residue pitch when one component was dichotic and the other was spectral as when the components were both spectral or both dichotic.This suggests that there exists a single mechanism for the derivation of residue pitch from binaurally created components and from spectral components, and that this mechanism operates at or after the level of the dorsal nucleus of the lateral lemniscus (brainstem) or the inferior colliculus (midbrain), which receive inputs from the medial superior olive where temporal information from the two ears is first combined.

View Article: PubMed Central - PubMed

Affiliation: MRC Cognition and Brain Sciences Unit, 15 Chaucer Road, Cambridge, UK. hedwig.gockel@mrc-cbu.cam.ac.uk

ABSTRACT
A fundamental attribute of human hearing is the ability to extract a residue pitch from harmonic complex sounds such as those produced by musical instruments and the human voice. However, the neural mechanisms that underlie this processing are unclear, as are the locations of these mechanisms in the auditory pathway. The ability to extract a residue pitch corresponding to the fundamental frequency from individual harmonics, even when the fundamental component is absent, has been demonstrated separately for conventional pitches and for Huggins pitch (HP), a stimulus without monaural pitch information. HP is created by presenting the same wideband noise to both ears, except for a narrowband frequency region where the noise is decorrelated across the two ears. The present study investigated whether residue pitch can be derived by combining a component derived solely from binaural interaction (HP) with a spectral component for which no binaural processing is required. Fifteen listeners indicated which of two sequentially presented sounds was higher in pitch. Each sound consisted of two "harmonics," which independently could be either a spectral or a HP component. Component frequencies were chosen such that the relative pitch judgement revealed whether a residue pitch was heard or not. The results showed that listeners were equally likely to perceive a residue pitch when one component was dichotic and the other was spectral as when the components were both spectral or both dichotic. This suggests that there exists a single mechanism for the derivation of residue pitch from binaurally created components and from spectral components, and that this mechanism operates at or after the level of the dorsal nucleus of the lateral lemniscus (brainstem) or the inferior colliculus (midbrain), which receive inputs from the medial superior olive where temporal information from the two ears is first combined.

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