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A neuronal network model for context-dependence of pitch change perception.

Huang C, Englitz B, Shamma S, Rinzel J - Front Comput Neurosci (2015)

Bottom Line: We developed a recurrent, firing-rate network model, which detects frequency-change-direction of successively played stimuli and successfully accounts for the context-dependent perception demonstrated in behavioral experiments.The model's network architecture and slow facilitating inhibition emerge as predictions of neuronal mechanisms for these perceptual dynamics.Since the model structure does not depend on the specific stimuli, we show that it generalizes to other contextual effects and stimulus types.

View Article: PubMed Central - PubMed

Affiliation: Courant Institute of Mathematical Sciences, New York University New York, NY, USA.

ABSTRACT
Many natural stimuli have perceptual ambiguities that can be cognitively resolved by the surrounding context. In audition, preceding context can bias the perception of speech and non-speech stimuli. Here, we develop a neuronal network model that can account for how context affects the perception of pitch change between a pair of successive complex tones. We focus especially on an ambiguous comparison-listeners experience opposite percepts (either ascending or descending) for an ambiguous tone pair depending on the spectral location of preceding context tones. We developed a recurrent, firing-rate network model, which detects frequency-change-direction of successively played stimuli and successfully accounts for the context-dependent perception demonstrated in behavioral experiments. The model consists of two tonotopically organized, excitatory populations, E up and E down, that respond preferentially to ascending or descending stimuli in pitch, respectively. These preferences are generated by an inhibitory population that provides inhibition asymmetric in frequency to the two populations; context dependence arises from slow facilitation of inhibition. We show that contextual influence depends on the spectral distribution of preceding tones and the tuning width of inhibitory neurons. Further, we demonstrate, using phase-space analysis, how the facilitated inhibition from previous stimuli and the waning inhibition from the just-preceding tone shape the competition between the E up and E down populations. In sum, our model accounts for contextual influences on the pitch change perception of an ambiguous tone pair by introducing a novel decoding strategy based on direction-selective units. The model's network architecture and slow facilitating inhibition emerge as predictions of neuronal mechanisms for these perceptual dynamics. Since the model structure does not depend on the specific stimuli, we show that it generalizes to other contextual effects and stimulus types.

No MeSH data available.


Related in: MedlinePlus

The Psychophysical experiment paradigm and summary of behavioral results. (A) Schematic of Shepard tones (details see Materials and Methods). A Shepard tone consists of multiple octave-spaced pure tones. Due to the periodic spectral structure of Shepard tones, we can represent each tone by its pitch class within one octave (between the two gray lines). A tritone pair is two Shepard tones separated by a half-octave, for example the tones at pitch classes 0 st (middle) and 6 st (right). (B) Stimuli examples in tritone comparison with preceding bias tones. The bias tones are randomly sampled in the region either above (Up bias) or below (Down bias) the first test tone (T1). T1 and T2 is a tritone pair, separated by a half-octave (6 st). (C) Steps of 0–6 st from T1 (tones at the right half of the pitch class circle) are perceived as ascending while steps of -6–0 st (tones at the left half circle) are perceived as descending (Shepard, 1964; Chambers and Pressnitzer, 2014). Up bias tones bias the perception of the ambiguous tritone pair (T1 and T2) toward ascending while Down bias tones bias toward descending (Englitz et al., 2013, Figure 18.1D, see Supplementary Material for audio demonstrations). [A,B are modified from Englitz et al. (2013). (Figures 18.1A,C)].
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Figure 1: The Psychophysical experiment paradigm and summary of behavioral results. (A) Schematic of Shepard tones (details see Materials and Methods). A Shepard tone consists of multiple octave-spaced pure tones. Due to the periodic spectral structure of Shepard tones, we can represent each tone by its pitch class within one octave (between the two gray lines). A tritone pair is two Shepard tones separated by a half-octave, for example the tones at pitch classes 0 st (middle) and 6 st (right). (B) Stimuli examples in tritone comparison with preceding bias tones. The bias tones are randomly sampled in the region either above (Up bias) or below (Down bias) the first test tone (T1). T1 and T2 is a tritone pair, separated by a half-octave (6 st). (C) Steps of 0–6 st from T1 (tones at the right half of the pitch class circle) are perceived as ascending while steps of -6–0 st (tones at the left half circle) are perceived as descending (Shepard, 1964; Chambers and Pressnitzer, 2014). Up bias tones bias the perception of the ambiguous tritone pair (T1 and T2) toward ascending while Down bias tones bias toward descending (Englitz et al., 2013, Figure 18.1D, see Supplementary Material for audio demonstrations). [A,B are modified from Englitz et al. (2013). (Figures 18.1A,C)].

Mentions: The psychophysical experiments (Repp, 1997; Englitz et al., 2013) adopt Shepard tones, each of which consists of multiple simultaneous octave-spaced pure tones (Figure 1A). A Shepard tone with many frequency components is approximately spectrally periodic. Shepard tones are famous for being used to create the auditory illusion of an ever-ascending sequence of tones. This is done by incrementing the pitch class (PC), note name in music, by 1 semitone (st) at a time, although the sequence repeats itself for every 12 tones due to the spectral periodicity (1 octave is 12 st) (Shepard, 1964). When two Shepard tones are separated by a half-octave (tritone) (e.g., tones at PC = 0 and 6 st in Figure 1A), the pitch change direction is ambiguous and the directional percept of the same tritone pair varies among subjects (Deutsch, 1986, 1991; Deutsch et al., 1990). Strong hysteresis effects have been shown for tritone pairs (Giangrande et al., 2003; Chambers and Pressnitzer, 2014), suggesting that directional percepts of tritone pairs are very susceptible to preceding stimuli, i.e., context. (Repp, 1997 Experiment 3) found that a single Shepard tone before a tritone pair influences the perceived pitch change direction. A few preceding Shepard tones with PC between the tritone pair can strongly bias the perception toward the direction from the first (T1) to the second tone (T2)—ascending if the sequence is within the half-octave interval above T1, and vice versa if below T1(Englitz et al., 2013, see Figure 18.1D; Chambers and Pressnitzer, 2011) (Figures 1B,C; for details see Materials and Methods, see Supplementary Material for audio demonstrations).


A neuronal network model for context-dependence of pitch change perception.

Huang C, Englitz B, Shamma S, Rinzel J - Front Comput Neurosci (2015)

The Psychophysical experiment paradigm and summary of behavioral results. (A) Schematic of Shepard tones (details see Materials and Methods). A Shepard tone consists of multiple octave-spaced pure tones. Due to the periodic spectral structure of Shepard tones, we can represent each tone by its pitch class within one octave (between the two gray lines). A tritone pair is two Shepard tones separated by a half-octave, for example the tones at pitch classes 0 st (middle) and 6 st (right). (B) Stimuli examples in tritone comparison with preceding bias tones. The bias tones are randomly sampled in the region either above (Up bias) or below (Down bias) the first test tone (T1). T1 and T2 is a tritone pair, separated by a half-octave (6 st). (C) Steps of 0–6 st from T1 (tones at the right half of the pitch class circle) are perceived as ascending while steps of -6–0 st (tones at the left half circle) are perceived as descending (Shepard, 1964; Chambers and Pressnitzer, 2014). Up bias tones bias the perception of the ambiguous tritone pair (T1 and T2) toward ascending while Down bias tones bias toward descending (Englitz et al., 2013, Figure 18.1D, see Supplementary Material for audio demonstrations). [A,B are modified from Englitz et al. (2013). (Figures 18.1A,C)].
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Figure 1: The Psychophysical experiment paradigm and summary of behavioral results. (A) Schematic of Shepard tones (details see Materials and Methods). A Shepard tone consists of multiple octave-spaced pure tones. Due to the periodic spectral structure of Shepard tones, we can represent each tone by its pitch class within one octave (between the two gray lines). A tritone pair is two Shepard tones separated by a half-octave, for example the tones at pitch classes 0 st (middle) and 6 st (right). (B) Stimuli examples in tritone comparison with preceding bias tones. The bias tones are randomly sampled in the region either above (Up bias) or below (Down bias) the first test tone (T1). T1 and T2 is a tritone pair, separated by a half-octave (6 st). (C) Steps of 0–6 st from T1 (tones at the right half of the pitch class circle) are perceived as ascending while steps of -6–0 st (tones at the left half circle) are perceived as descending (Shepard, 1964; Chambers and Pressnitzer, 2014). Up bias tones bias the perception of the ambiguous tritone pair (T1 and T2) toward ascending while Down bias tones bias toward descending (Englitz et al., 2013, Figure 18.1D, see Supplementary Material for audio demonstrations). [A,B are modified from Englitz et al. (2013). (Figures 18.1A,C)].
Mentions: The psychophysical experiments (Repp, 1997; Englitz et al., 2013) adopt Shepard tones, each of which consists of multiple simultaneous octave-spaced pure tones (Figure 1A). A Shepard tone with many frequency components is approximately spectrally periodic. Shepard tones are famous for being used to create the auditory illusion of an ever-ascending sequence of tones. This is done by incrementing the pitch class (PC), note name in music, by 1 semitone (st) at a time, although the sequence repeats itself for every 12 tones due to the spectral periodicity (1 octave is 12 st) (Shepard, 1964). When two Shepard tones are separated by a half-octave (tritone) (e.g., tones at PC = 0 and 6 st in Figure 1A), the pitch change direction is ambiguous and the directional percept of the same tritone pair varies among subjects (Deutsch, 1986, 1991; Deutsch et al., 1990). Strong hysteresis effects have been shown for tritone pairs (Giangrande et al., 2003; Chambers and Pressnitzer, 2014), suggesting that directional percepts of tritone pairs are very susceptible to preceding stimuli, i.e., context. (Repp, 1997 Experiment 3) found that a single Shepard tone before a tritone pair influences the perceived pitch change direction. A few preceding Shepard tones with PC between the tritone pair can strongly bias the perception toward the direction from the first (T1) to the second tone (T2)—ascending if the sequence is within the half-octave interval above T1, and vice versa if below T1(Englitz et al., 2013, see Figure 18.1D; Chambers and Pressnitzer, 2011) (Figures 1B,C; for details see Materials and Methods, see Supplementary Material for audio demonstrations).

Bottom Line: We developed a recurrent, firing-rate network model, which detects frequency-change-direction of successively played stimuli and successfully accounts for the context-dependent perception demonstrated in behavioral experiments.The model's network architecture and slow facilitating inhibition emerge as predictions of neuronal mechanisms for these perceptual dynamics.Since the model structure does not depend on the specific stimuli, we show that it generalizes to other contextual effects and stimulus types.

View Article: PubMed Central - PubMed

Affiliation: Courant Institute of Mathematical Sciences, New York University New York, NY, USA.

ABSTRACT
Many natural stimuli have perceptual ambiguities that can be cognitively resolved by the surrounding context. In audition, preceding context can bias the perception of speech and non-speech stimuli. Here, we develop a neuronal network model that can account for how context affects the perception of pitch change between a pair of successive complex tones. We focus especially on an ambiguous comparison-listeners experience opposite percepts (either ascending or descending) for an ambiguous tone pair depending on the spectral location of preceding context tones. We developed a recurrent, firing-rate network model, which detects frequency-change-direction of successively played stimuli and successfully accounts for the context-dependent perception demonstrated in behavioral experiments. The model consists of two tonotopically organized, excitatory populations, E up and E down, that respond preferentially to ascending or descending stimuli in pitch, respectively. These preferences are generated by an inhibitory population that provides inhibition asymmetric in frequency to the two populations; context dependence arises from slow facilitation of inhibition. We show that contextual influence depends on the spectral distribution of preceding tones and the tuning width of inhibitory neurons. Further, we demonstrate, using phase-space analysis, how the facilitated inhibition from previous stimuli and the waning inhibition from the just-preceding tone shape the competition between the E up and E down populations. In sum, our model accounts for contextual influences on the pitch change perception of an ambiguous tone pair by introducing a novel decoding strategy based on direction-selective units. The model's network architecture and slow facilitating inhibition emerge as predictions of neuronal mechanisms for these perceptual dynamics. Since the model structure does not depend on the specific stimuli, we show that it generalizes to other contextual effects and stimulus types.

No MeSH data available.


Related in: MedlinePlus