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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.

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Non-uniform inhibitory synaptic strengths lead to a sinusoidal-like pattern of outcomes for tritone comparisons. (A) Response difference of Eup and Edown to tritone pairs at different pitch classes without context. The inhibitory pre-synaptic strength aie depends on the pitch class of I neurons. The profile of aie is shown in (B). Mean relative population activity difference, D (Equation 6, see Materials and Methods), of Eup and Edown during T2 has a sinusoidal-like pattern, varying with the pitch class of the second tone T2. A positive D predicts “ascending” response and negative D predicts “descending.” The pitch classes of T2 with largest response difference /D/ correspond to where aie changes most steeply. (B) The dependence of inhibitory pre-synaptic strength, aie, on pitch class of I neurons. In this simulation, the inhibitory synaptic current, , in Equation (4) is given as: , α= up, down.
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Figure 7: Non-uniform inhibitory synaptic strengths lead to a sinusoidal-like pattern of outcomes for tritone comparisons. (A) Response difference of Eup and Edown to tritone pairs at different pitch classes without context. The inhibitory pre-synaptic strength aie depends on the pitch class of I neurons. The profile of aie is shown in (B). Mean relative population activity difference, D (Equation 6, see Materials and Methods), of Eup and Edown during T2 has a sinusoidal-like pattern, varying with the pitch class of the second tone T2. A positive D predicts “ascending” response and negative D predicts “descending.” The pitch classes of T2 with largest response difference /D/ correspond to where aie changes most steeply. (B) The dependence of inhibitory pre-synaptic strength, aie, on pitch class of I neurons. In this simulation, the inhibitory synaptic current, , in Equation (4) is given as: , α= up, down.

Mentions: Our model provides a plausible explanation for individual variations in the tritone comparison among and across individuals. The variability across subjects, i.e., perceiving different directions on average for the same tritone pair, has been termed the tritone paradox (Deutsch, 1986; Deutsch et al., 1990). Moreover, individual responses to tritone pairs (half-octave apart) often show a dependence on PC with a sinusoidal-like pattern (Figure 7A). Instead of being around chance level for a tritone pair of any PC, some pitch classes are more likely to be heard as the higher of a tritone pair, while some pitch classes are more likely to be heard as the lower (Deutsch et al., 1990, see Figure 3; Deutsch, 1991, see Figure 3). Such sinusoidal patterns for tritone comparison vary among subjects and are found to correlate with language (Deutsch, 1991) and the vocal range of one's speech (Deutsch et al., 1990). Our model can reproduce the sinusoidal-like pattern of individual tritone responses using a heterogeneous inhibitory population with pre-synaptic strength, aie, depending on PC (Figure 7B). Different distributions of inhibitory synaptic strengths give different sinusoidal-like patterns as a function of PC, which can account for the individual variations across subjects.


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

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

Non-uniform inhibitory synaptic strengths lead to a sinusoidal-like pattern of outcomes for tritone comparisons. (A) Response difference of Eup and Edown to tritone pairs at different pitch classes without context. The inhibitory pre-synaptic strength aie depends on the pitch class of I neurons. The profile of aie is shown in (B). Mean relative population activity difference, D (Equation 6, see Materials and Methods), of Eup and Edown during T2 has a sinusoidal-like pattern, varying with the pitch class of the second tone T2. A positive D predicts “ascending” response and negative D predicts “descending.” The pitch classes of T2 with largest response difference /D/ correspond to where aie changes most steeply. (B) The dependence of inhibitory pre-synaptic strength, aie, on pitch class of I neurons. In this simulation, the inhibitory synaptic current, , in Equation (4) is given as: , α= up, down.
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
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Figure 7: Non-uniform inhibitory synaptic strengths lead to a sinusoidal-like pattern of outcomes for tritone comparisons. (A) Response difference of Eup and Edown to tritone pairs at different pitch classes without context. The inhibitory pre-synaptic strength aie depends on the pitch class of I neurons. The profile of aie is shown in (B). Mean relative population activity difference, D (Equation 6, see Materials and Methods), of Eup and Edown during T2 has a sinusoidal-like pattern, varying with the pitch class of the second tone T2. A positive D predicts “ascending” response and negative D predicts “descending.” The pitch classes of T2 with largest response difference /D/ correspond to where aie changes most steeply. (B) The dependence of inhibitory pre-synaptic strength, aie, on pitch class of I neurons. In this simulation, the inhibitory synaptic current, , in Equation (4) is given as: , α= up, down.
Mentions: Our model provides a plausible explanation for individual variations in the tritone comparison among and across individuals. The variability across subjects, i.e., perceiving different directions on average for the same tritone pair, has been termed the tritone paradox (Deutsch, 1986; Deutsch et al., 1990). Moreover, individual responses to tritone pairs (half-octave apart) often show a dependence on PC with a sinusoidal-like pattern (Figure 7A). Instead of being around chance level for a tritone pair of any PC, some pitch classes are more likely to be heard as the higher of a tritone pair, while some pitch classes are more likely to be heard as the lower (Deutsch et al., 1990, see Figure 3; Deutsch, 1991, see Figure 3). Such sinusoidal patterns for tritone comparison vary among subjects and are found to correlate with language (Deutsch, 1991) and the vocal range of one's speech (Deutsch et al., 1990). Our model can reproduce the sinusoidal-like pattern of individual tritone responses using a heterogeneous inhibitory population with pre-synaptic strength, aie, depending on PC (Figure 7B). Different distributions of inhibitory synaptic strengths give different sinusoidal-like patterns as a function of PC, which can account for the individual variations across subjects.

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