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.


Correlation analyses between speech motor behavior and neural component amplitude. Adapters are shown in yellow, controls in purple. (A) Correlation between standardized F1 (representing change in F1 in the speech training session compared to baseline) and the difference in P2 amplitude during perception of the trained vowel (step one). (B) Correlation between standardized F1 (representing change in F1 in the speech training session compared to baseline) and the difference in N1 (1ms) amplitude during perception of the most ambiguous vowel (step three). (C) Correlation between average F1 in the speech training task and P2 amplitude averaged over all stimuli in the post-training identification session.
© Copyright Policy
Related In: Results  -  Collection

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

Figure 5: Correlation analyses between speech motor behavior and neural component amplitude. Adapters are shown in yellow, controls in purple. (A) Correlation between standardized F1 (representing change in F1 in the speech training session compared to baseline) and the difference in P2 amplitude during perception of the trained vowel (step one). (B) Correlation between standardized F1 (representing change in F1 in the speech training session compared to baseline) and the difference in N1 (1ms) amplitude during perception of the most ambiguous vowel (step three). (C) Correlation between average F1 in the speech training task and P2 amplitude averaged over all stimuli in the post-training identification session.

Mentions: For stimulus step one (clear [ɛ]), we found a significant correlation between changes in P2 amplitude and standardized F1 (Figure 5A: rho = −0.43, p = 0.006). Follow-up testing revealed no significant within-group correlations. The direction of the correlation indicated that participants who produced vowels with a lower F1 during the training session tended to show increases in P2 amplitude following training, and vice versa. This result runs counter to that found by Ito et al. (2016), in which compensatory adaptation led to decreases in P2 amplitude. However, it is important to note that the feedback shift in their study was opposite in direction to that utilized in this study. For stimulus step three (most ambiguous step), changes in N1 amplitude were also found to correlate with standardized F1 (Figure 5B: rho = 0.44, p = 0.005). These correlations were not significant within either group alone. As most of the between-session changes in perception were localized to this stimulus step (Figure 2B), this might indicate that changes in amplitude of this earlier component drove changes in perception. For stimulus step five (clear [ɪ]), standardized F1 was not found to correlate with either N1 amplitude (r = 0.018, p = 0.91) or P2 amplitude (r = −0.009, p = 0.96). Overall, these correlations indicate that changes in cortical responses to specific stimulus steps (one and three) were related to changes in vowel production.


Mapping the Speech Code: Cortical Responses Linking the Perception and Production of Vowels
Correlation analyses between speech motor behavior and neural component amplitude. Adapters are shown in yellow, controls in purple. (A) Correlation between standardized F1 (representing change in F1 in the speech training session compared to baseline) and the difference in P2 amplitude during perception of the trained vowel (step one). (B) Correlation between standardized F1 (representing change in F1 in the speech training session compared to baseline) and the difference in N1 (1ms) amplitude during perception of the most ambiguous vowel (step three). (C) Correlation between average F1 in the speech training task and P2 amplitude averaged over all stimuli in the post-training identification session.
© Copyright Policy
Related In: Results  -  Collection

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

Figure 5: Correlation analyses between speech motor behavior and neural component amplitude. Adapters are shown in yellow, controls in purple. (A) Correlation between standardized F1 (representing change in F1 in the speech training session compared to baseline) and the difference in P2 amplitude during perception of the trained vowel (step one). (B) Correlation between standardized F1 (representing change in F1 in the speech training session compared to baseline) and the difference in N1 (1ms) amplitude during perception of the most ambiguous vowel (step three). (C) Correlation between average F1 in the speech training task and P2 amplitude averaged over all stimuli in the post-training identification session.
Mentions: For stimulus step one (clear [ɛ]), we found a significant correlation between changes in P2 amplitude and standardized F1 (Figure 5A: rho = −0.43, p = 0.006). Follow-up testing revealed no significant within-group correlations. The direction of the correlation indicated that participants who produced vowels with a lower F1 during the training session tended to show increases in P2 amplitude following training, and vice versa. This result runs counter to that found by Ito et al. (2016), in which compensatory adaptation led to decreases in P2 amplitude. However, it is important to note that the feedback shift in their study was opposite in direction to that utilized in this study. For stimulus step three (most ambiguous step), changes in N1 amplitude were also found to correlate with standardized F1 (Figure 5B: rho = 0.44, p = 0.005). These correlations were not significant within either group alone. As most of the between-session changes in perception were localized to this stimulus step (Figure 2B), this might indicate that changes in amplitude of this earlier component drove changes in perception. For stimulus step five (clear [ɪ]), standardized F1 was not found to correlate with either N1 amplitude (r = 0.018, p = 0.91) or P2 amplitude (r = −0.009, p = 0.96). Overall, these correlations indicate that changes in cortical responses to specific stimulus steps (one and three) were related to changes in vowel production.

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.