Limits...
Mapping the Speech Code: Cortical Responses Linking the Perception and Production of Vowels

View Article: PubMed Central - PubMed

ABSTRACT

The acoustic realization of speech is constrained by the physical mechanisms by which it is produced. Yet for speech perception, the degree to which listeners utilize experience derived from speech production has long been debated. In the present study, we examined how sensorimotor adaptation during production may affect perception, and how this relationship may be reflected in early vs. late electrophysiological responses. Participants first performed a baseline speech production task, followed by a vowel categorization task during which EEG responses were recorded. In a subsequent speech production task, half the participants received shifted auditory feedback, leading most to alter their articulations. This was followed by a second, post-training vowel categorization task. We compared changes in vowel production to both behavioral and electrophysiological changes in vowel perception. No differences in phonetic categorization were observed between groups receiving altered or unaltered feedback. However, exploratory analyses revealed correlations between vocal motor behavior and phonetic categorization. EEG analyses revealed correlations between vocal motor behavior and cortical responses in both early and late time windows. These results suggest that participants' recent production behavior influenced subsequent vowel perception. We suggest that the change in perception can be best characterized as a mapping of acoustics onto articulation.

No MeSH data available.


Experimental design and production data. In the two speaking task (baseline and training), participants repeatedly produced the Dutch word “pet” (cap), which contains the front-mid vowel [ɛ]. Phonetic categorization tasks took place immediately after the end of the baseline (trial 50) and training sessions (trial 150). For both groups, feedback was unaltered during the baseline session (left panel). For the altered feedback group, the value of F1 in the auditory feedback increased linearly between trials 51 and 70 to a maximum of 25% greater than each trial's original value (inset, top right). Thus, participants heard themselves producing a more [æ]-like vowel, which led to compensatory decreases in F1 (yellow line). Feedback was unaltered for controls (purple line).
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC5383703&req=5

Figure 1: Experimental design and production data. In the two speaking task (baseline and training), participants repeatedly produced the Dutch word “pet” (cap), which contains the front-mid vowel [ɛ]. Phonetic categorization tasks took place immediately after the end of the baseline (trial 50) and training sessions (trial 150). For both groups, feedback was unaltered during the baseline session (left panel). For the altered feedback group, the value of F1 in the auditory feedback increased linearly between trials 51 and 70 to a maximum of 25% greater than each trial's original value (inset, top right). Thus, participants heard themselves producing a more [æ]-like vowel, which led to compensatory decreases in F1 (yellow line). Feedback was unaltered for controls (purple line).

Mentions: The present study sought to build upon these results in order to further explore how speech perception may reflect sensorimotor experience. We compared behavioral and cortical responses during a phonetic categorization task prior to and following sensorimotor training of speech production. Dutch participants were recorded producing the Dutch word “pet” (“cap”) containing the front mid-vowel [ɛ], and then performed a phonetic categorization task during which EEG was recorded. For the categorization task, we parametrically varied values of F1 to create a five-step continuum between [ɛ] and [ɪ]. In the subsequent speech training session, half of the participants were exposed to altered auditory feedback (the AF group) while the other half received unaltered feedback (the UF group). For the AF group, the value of F1 was increased, which caused participants to hear themselves producing a vowel more like [æ]. Compensating for this shifted feedback required articulating into a motor space that would normally produce a sound between [ɛ] and [ɪ], which in previous experiments had been found to lead to phonetic recalibration (Lametti et al., 2014). This training session was followed by another phonetic categorization task (Figure 1). The design enabled us to examine how changes in phonetic recalibration were related to changes in speech motor behavior, and how changes in speech motor behavior and phonetic categorization were reflected in electrophysiological responses.


Mapping the Speech Code: Cortical Responses Linking the Perception and Production of Vowels
Experimental design and production data. In the two speaking task (baseline and training), participants repeatedly produced the Dutch word “pet” (cap), which contains the front-mid vowel [ɛ]. Phonetic categorization tasks took place immediately after the end of the baseline (trial 50) and training sessions (trial 150). For both groups, feedback was unaltered during the baseline session (left panel). For the altered feedback group, the value of F1 in the auditory feedback increased linearly between trials 51 and 70 to a maximum of 25% greater than each trial's original value (inset, top right). Thus, participants heard themselves producing a more [æ]-like vowel, which led to compensatory decreases in F1 (yellow line). Feedback was unaltered for controls (purple line).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5383703&req=5

Figure 1: Experimental design and production data. In the two speaking task (baseline and training), participants repeatedly produced the Dutch word “pet” (cap), which contains the front-mid vowel [ɛ]. Phonetic categorization tasks took place immediately after the end of the baseline (trial 50) and training sessions (trial 150). For both groups, feedback was unaltered during the baseline session (left panel). For the altered feedback group, the value of F1 in the auditory feedback increased linearly between trials 51 and 70 to a maximum of 25% greater than each trial's original value (inset, top right). Thus, participants heard themselves producing a more [æ]-like vowel, which led to compensatory decreases in F1 (yellow line). Feedback was unaltered for controls (purple line).
Mentions: The present study sought to build upon these results in order to further explore how speech perception may reflect sensorimotor experience. We compared behavioral and cortical responses during a phonetic categorization task prior to and following sensorimotor training of speech production. Dutch participants were recorded producing the Dutch word “pet” (“cap”) containing the front mid-vowel [ɛ], and then performed a phonetic categorization task during which EEG was recorded. For the categorization task, we parametrically varied values of F1 to create a five-step continuum between [ɛ] and [ɪ]. In the subsequent speech training session, half of the participants were exposed to altered auditory feedback (the AF group) while the other half received unaltered feedback (the UF group). For the AF group, the value of F1 was increased, which caused participants to hear themselves producing a vowel more like [æ]. Compensating for this shifted feedback required articulating into a motor space that would normally produce a sound between [ɛ] and [ɪ], which in previous experiments had been found to lead to phonetic recalibration (Lametti et al., 2014). This training session was followed by another phonetic categorization task (Figure 1). The design enabled us to examine how changes in phonetic recalibration were related to changes in speech motor behavior, and how changes in speech motor behavior and phonetic categorization were reflected in electrophysiological responses.

View Article: PubMed Central - PubMed

ABSTRACT

The acoustic realization of speech is constrained by the physical mechanisms by which it is produced. Yet for speech perception, the degree to which listeners utilize experience derived from speech production has long been debated. In the present study, we examined how sensorimotor adaptation during production may affect perception, and how this relationship may be reflected in early vs. late electrophysiological responses. Participants first performed a baseline speech production task, followed by a vowel categorization task during which EEG responses were recorded. In a subsequent speech production task, half the participants received shifted auditory feedback, leading most to alter their articulations. This was followed by a second, post-training vowel categorization task. We compared changes in vowel production to both behavioral and electrophysiological changes in vowel perception. No differences in phonetic categorization were observed between groups receiving altered or unaltered feedback. However, exploratory analyses revealed correlations between vocal motor behavior and phonetic categorization. EEG analyses revealed correlations between vocal motor behavior and cortical responses in both early and late time windows. These results suggest that participants' recent production behavior influenced subsequent vowel perception. We suggest that the change in perception can be best characterized as a mapping of acoustics onto articulation.

No MeSH data available.