scholarly journals Left frontal motor delta oscillations reflect the temporal integration of multimodal speech

2020 ◽  
Author(s):  
Emmanuel Biau ◽  
Benjamin G. Schultz ◽  
Thomas C. Gunter ◽  
Sonja A. Kotz
Keyword(s):  
Speech Perception ◽  
Speech Signal ◽  
Temporal Structure ◽  
Temporal Integration ◽  
Oscillatory Activity ◽  
Prosodic Features ◽  
Temporal Alignment ◽  
Delta Activity ◽  
Verbal Content ◽  
Delta Oscillations

ABSTRACTDuring multimodal speech perception, slow delta oscillations (~1 - 3 Hz) in the listener’s brain synchronize with speech signal, likely reflecting signal decomposition at the service of comprehension. In particular, fluctuations imposed onto the speech amplitude envelope by a speaker’s prosody seem to temporally align with articulatory and body gestures, thus providing two complementary sensations to the speech signal’s temporal structure. Further, endogenous delta oscillations in the left motor cortex align with speech and music beat, suggesting a role in the temporal integration of (quasi)-rhythmic stimulations. We propose that delta activity facilitates the temporal alignment of a listener’s oscillatory activity with the prosodic fluctuations in a speaker’s speech during multimodal speech perception. We recorded EEG responses in an audiovisual synchrony detection task while participants watched videos of a speaker. To test the temporal alignment of visual and auditory prosodic features, we filtered the speech signal to remove verbal content. Results confirm (i) that participants accurately detected audiovisual synchrony, and (ii) greater delta power in left frontal motor regions in response to audiovisual asynchrony. The latter effect correlated with behavioural performance, and (iii) decreased delta-beta coupling in the left frontal motor regions when listeners could not accurately integrate visual and auditory prosodies. Together, these findings suggest that endogenous delta oscillations align fluctuating prosodic information conveyed by distinct sensory modalities onto a common temporal organisation in multimodal speech perception.

scholarly journals Zebra finches are sensitive to prosodic features of human speech

2014 ◽  
Vol 281 (1787) ◽  
pp. 20140480 ◽  
Author(s):  
Michelle J. Spierings ◽  
Carel ten Cate
Keyword(s):  
Speech Perception ◽  
Emotional State ◽  
The Other ◽  
Zebra Finches ◽  
Prosodic Features ◽  
Human Speech ◽  
Prosodic Cues ◽  
Paralinguistic Information ◽  
Final Syllable ◽  
Human Specific

Variation in pitch, amplitude and rhythm adds crucial paralinguistic information to human speech. Such prosodic cues can reveal information about the meaning or emphasis of a sentence or the emotional state of the speaker. To examine the hypothesis that sensitivity to prosodic cues is language independent and not human specific, we tested prosody perception in a controlled experiment with zebra finches. Using a go/no-go procedure, subjects were trained to discriminate between speech syllables arranged in XYXY patterns with prosodic stress on the first syllable and XXYY patterns with prosodic stress on the final syllable. To systematically determine the salience of the various prosodic cues (pitch, duration and amplitude) to the zebra finches, they were subjected to five tests with different combinations of these cues. The zebra finches generalized the prosodic pattern to sequences that consisted of new syllables and used prosodic features over structural ones to discriminate between stimuli. This strong sensitivity to the prosodic pattern was maintained when only a single prosodic cue was available. The change in pitch was treated as more salient than changes in the other prosodic features. These results show that zebra finches are sensitive to the same prosodic cues known to affect human speech perception.

scholarly journals Cortical entrainment to music and its modulation by expertise

2015 ◽  
Vol 112 (45) ◽  
pp. E6233-E6242 ◽  
Author(s):  
Keith B. Doelling ◽  
David Poeppel
Keyword(s):  
Music Perception ◽  
Musical Training ◽  
Low Frequency ◽  
Oscillatory Activity ◽  
Cortical Oscillations ◽  
Bidirectional Relationship ◽  
Delta Activity ◽  
Tightly Coupled ◽  
Neural Entrainment ◽  
Cortical Entrainment

Recent studies establish that cortical oscillations track naturalistic speech in a remarkably faithful way. Here, we test whether such neural activity, particularly low-frequency (<8 Hz; delta–theta) oscillations, similarly entrain to music and whether experience modifies such a cortical phenomenon. Music of varying tempi was used to test entrainment at different rates. In three magnetoencephalography experiments, we recorded from nonmusicians, as well as musicians with varying years of experience. Recordings from nonmusicians demonstrate cortical entrainment that tracks musical stimuli over a typical range of tempi, but not at tempi below 1 note per second. Importantly, the observed entrainment correlates with performance on a concurrent pitch-related behavioral task. In contrast, the data from musicians show that entrainment is enhanced by years of musical training, at all presented tempi. This suggests a bidirectional relationship between behavior and cortical entrainment, a phenomenon that has not previously been reported. Additional analyses focus on responses in the beta range (∼15–30 Hz)—often linked to delta activity in the context of temporal predictions. Our findings provide evidence that the role of beta in temporal predictions scales to the complex hierarchical rhythms in natural music and enhances processing of musical content. This study builds on important findings on brainstem plasticity and represents a compelling demonstration that cortical neural entrainment is tightly coupled to both musical training and task performance, further supporting a role for cortical oscillatory activity in music perception and cognition.

Consciousness among delta waves: a paradox?

Brain ◽  
2021 ◽  
Author(s):  
Joel Frohlich ◽  
Daniel Toker ◽  
Martin M Monti
Keyword(s):  
Slow Wave Sleep ◽  
Spectral Power ◽  
Vegetative State ◽  
Mitochondrial Diseases ◽  
Epileptic Seizures ◽  
High Amplitude ◽  
Convincing Evidence ◽  
Delta Activity ◽  
Parallel Body ◽  
Delta Oscillations

Abstract A common observation in EEG research is that consciousness vanishes with the appearance of delta (1 – 4 Hz) waves, particularly when those waves are high amplitude. High amplitude delta oscillations are very frequently observed in states of diminished consciousness, including slow wave sleep, anaesthesia, generalised epileptic seizures, and disorders of consciousness such as coma and vegetative state. This strong correlation between loss of consciousness and high amplitude delta oscillations is thought to stem from the widespread cortical deactivation that occurs during the “down states” or troughs of these slow oscillations. Recently, however, many studies have reported the presence of prominent delta activity during conscious states, which casts doubt on the hypothesis that high amplitude delta oscillations are an indicator of unconsciousness. These studies include work in Angelman syndrome, epilepsy, behavioural responsiveness during propofol anaesthesia, postoperative delirium, and states of dissociation from the environment such as dreaming and powerful psychedelic states. The foregoing studies complement an older, yet largely unacknowledged, body of literature that has documented awake, conscious patients with high amplitude delta oscillations in clinical reports from Rett syndrome, Lennox-Gastaut syndrome, schizophrenia, mitochondrial diseases, hepatic encephalopathy, and nonconvulsive status epilepticus. At the same time, a largely parallel body of recent work has reported convincing evidence that the complexity or entropy of EEG and magnetoencephalogram or MEG signals strongly relates to an individual’s level of consciousness. Having reviewed this literature, we discuss plausible mechanisms that would resolve the seeming contradiction between high amplitude delta oscillations and consciousness. We also consider implications concerning theories of consciousness, such as integrated information theory and the entropic brain hypothesis. Finally, we conclude that false inferences of unconscious states can be best avoided by examining measures of electrophysiological complexity in addition to spectral power.

Communication of Speech Sounds by a Tactual Vocoder

1963 ◽  
Vol 6 (3) ◽  
pp. 207-222 ◽  
Author(s):  
J. M. Pickett ◽  
B. Horenstein Pickett
Keyword(s):  
Speech Perception ◽  
Energy Distribution ◽  
Frequency Analysis ◽  
Speech Signal ◽  
Frequency Region ◽  
Speech Communication ◽  
Royal Institute ◽  
Speech Transmission ◽  
Institute Of Technology ◽  
Speech Information

Tests of tactual speech perception were conducted using a special frequency-analyzing vocoder. The vocoder presented a running frequency analysis of speech mapped into a spatial array of tactual vibrations which were applied to the fingers of the receiving subject. Ten vibrators were used, one for each finger. The position of a vibrator represented a given frequency region of speech energy; the total range covered was 210 to 7 700 cps; all the vibrations had a frequency of 300 cps; the vibration amplitudes represented the energy distribution over the various frequencies. Discrimination and identification tests were performed with various sets of test vowels; consonant discrimination tests were performed with certain consonants including those that might be difficult to lipread. Performance with vowels appeared to be related to formant structure and duration as measured on the test vowels, and to tactual masking effects. Consonant discrimination was good between stops and continuants; consonant features of nasality, voicing, and affrication were also discriminated to some extent. It is concluded that the skin offers certain capacities for transmitting speech information which may be used to complement speech communication where only an impoverished speech signal is normally received. This research was conducted at the Speech Transmission Laboratory, Royal Institute of Technology, Stockholm, Sweden.

scholarly journals Cortical Tracking of Global and Local Variations of Speech Rhythm during Connected Natural Speech Perception

2018 ◽  
Vol 30 (11) ◽  
pp. 1704-1719 ◽  
Author(s):  
Anna Maria Alexandrou ◽  
Timo Saarinen ◽  
Jan Kujala ◽  
Riitta Salmelin
Keyword(s):  
Speech Perception ◽  
Parietal Cortex ◽  
Temporal Structure ◽  
Temporal Cortex ◽  
Speaking Rate ◽  
Natural Speech ◽  
Speech Signals ◽  
Speech Rhythm ◽  
Linguistic Information ◽  
Evolutionary Tuning

During natural speech perception, listeners must track the global speaking rate, that is, the overall rate of incoming linguistic information, as well as transient, local speaking rate variations occurring within the global speaking rate. Here, we address the hypothesis that this tracking mechanism is achieved through coupling of cortical signals to the amplitude envelope of the perceived acoustic speech signals. Cortical signals were recorded with magnetoencephalography (MEG) while participants perceived spontaneously produced speech stimuli at three global speaking rates (slow, normal/habitual, and fast). Inherently to spontaneously produced speech, these stimuli also featured local variations in speaking rate. The coupling between cortical and acoustic speech signals was evaluated using audio–MEG coherence. Modulations in audio–MEG coherence spatially differentiated between tracking of global speaking rate, highlighting the temporal cortex bilaterally and the right parietal cortex, and sensitivity to local speaking rate variations, emphasizing the left parietal cortex. Cortical tuning to the temporal structure of natural connected speech thus seems to require the joint contribution of both auditory and parietal regions. These findings suggest that cortical tuning to speech rhythm operates on two functionally distinct levels: one encoding the global rhythmic structure of speech and the other associated with online, rapidly evolving temporal predictions. Thus, it may be proposed that speech perception is shaped by evolutionary tuning, a preference for certain speaking rates, and predictive tuning, associated with cortical tracking of the constantly changing-rate of linguistic information in a speech stream.

Integrating cues in speech perception

1998 ◽  
Vol 21 (2) ◽  
pp. 275-275 ◽  
Author(s):  
Dominic W. Massaro
Keyword(s):  
Speech Perception ◽  
Speech Signal ◽  
Perceptual Categorization ◽  
Important Goal ◽  
Multiple Cues ◽  
Ecological Property ◽  
Second Formant ◽  
Speech Research

Sussman et al. describe an ecological property of the speech signal that is putatively functional in perception. An important issue, however, is whether their putative cue is an emerging feature or whether the second formant (F2) onset and the F2 vowel actually provide independent cues to perceptual categorization. Regardless of the outcome of this issue, an important goal of speech research is to understand how multiple cues are evaluated and integrated to achieve categorization.

scholarly journals Perception of Rhythmic Speech Is Modulated by Focal Bilateral Transcranial Alternating Current Stimulation

2020 ◽  
Vol 32 (2) ◽  
pp. 226-240 ◽  
Author(s):  
Benedikt Zoefel ◽  
Isobella Allard ◽  
Megha Anil ◽  
Matthew H. Davis
Keyword(s):  
Speech Perception ◽  
Speech Processing ◽  
Alternating Current ◽  
Stream Segregation ◽  
Causal Role ◽  
Oscillatory Activity ◽  
Transcranial Alternating Current Stimulation ◽  
Neural Entrainment ◽  
Actual Speech

Several recent studies have used transcranial alternating current stimulation (tACS) to demonstrate a causal role of neural oscillatory activity in speech processing. In particular, it has been shown that the ability to understand speech in a multi-speaker scenario or background noise depends on the timing of speech presentation relative to simultaneously applied tACS. However, it is possible that tACS did not change actual speech perception but rather auditory stream segregation. In this study, we tested whether the phase relation between tACS and the rhythm of degraded words, presented in silence, modulates word report accuracy. We found strong evidence for a tACS-induced modulation of speech perception, but only if the stimulation was applied bilaterally using ring electrodes (not for unilateral left hemisphere stimulation with square electrodes). These results were only obtained when data were analyzed using a statistical approach that was identified as optimal in a previous simulation study. The effect was driven by a phasic disruption of word report scores. Our results suggest a causal role of neural entrainment for speech perception and emphasize the importance of optimizing stimulation protocols and statistical approaches for brain stimulation research.

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