| 1. |
- Stroganova, T. A., et al.
(författare)
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Effects of the Periodicity and Vowelness of Sounds on Auditory Cortex Responses in Children
- 2022
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Ingår i: Neuroscience and Behavioral Physiology. - : Springer Science and Business Media LLC. - 0097-0549 .- 1573-899X. ; 52:3, s. 395-404
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Tidskriftsartikel (refereegranskat)abstract
- The mechanisms of the human brain decoding speech sounds are of fundamental and applied interest in many areas of neuroscience. This study addresses the roles of periodicity and the speech nature (fixed formant structure) of vowel sounds in modulating auditory cortex activity in typically developing children. We proposed that both of these characteristics are typical of the vowel sounds of speech and that they are processed by different neural networks in the auditory cortex. To test this hypothesis, we constructed a set of acoustic stimuli by manipulating their periodicity and vowelness separately and used magnetoencephalography combined with individual models of the cortical surface to evaluate the cortical topography of the sources of auditory cortex responses and their strengths. The cohort consisted of nine typically developing children aged 7–12 years. We found that early auditory cortex responses (50–150 msec after stimulus onset) were highly sensitive to both the periodicity and vowelness of sounds, with independent tuning of neural networks to each of these properties of speech sounds. Differences in the locations, time dynamics, and hemisphere asymmetry of these differential responses indicated that “sound vowelness zones” in the temporal cortex constitute the earliest level in the speech information processing hierarchy at which processing of the acoustic properties of a periodic signal is transformed into decoding of speech sounds. These results allow the specific features and roles of possible impairments to the processing of the low-level properties of speech sounds and difficulties in speech perception in children with pervasive developmental disorders to be evaluated.
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| 2. |
- Stroganova, T. A., et al.
(författare)
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Left hemispheric deficit in the sustained neuromagnetic response to periodic click trains in children with ASD
- 2020
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Ingår i: Molecular Autism. - : Springer Science and Business Media LLC. - 2040-2392. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Background Deficits in perception and production of vocal pitch are often observed in people with autism spectrum disorder (ASD), but the neural basis of these deficits is unknown. In magnetoencephalogram (MEG), spectrally complex periodic sounds trigger two continuous neural responses-the auditory steady state response (ASSR) and the sustained field (SF). It has been shown that the SF in neurotypical individuals is associated with low-level analysis of pitch in the 'pitch processing center' of the Heschl's gyrus. Therefore, alternations in this auditory response may reflect atypical processing of vocal pitch. The SF, however, has never been studied in people with ASD. Methods We used MEG and individual brain models to investigate the ASSR and SF evoked by monaural 40 Hz click trains in boys with ASD (N = 35) and neurotypical (NT) boys (N = 35) aged 7-12-years. Results In agreement with the previous research in adults, the cortical sources of the SF in children were located in the left and right Heschl's gyri, anterolateral to those of the ASSR. In both groups, the SF and ASSR dominated in the right hemisphere and were higher in the hemisphere contralateral to the stimulated ear. The ASSR increased with age in both NT and ASD children and did not differ between the groups. The SF amplitude did not significantly change between the ages of 7 and 12 years. It was moderately attenuated in both hemispheres and was markedly delayed and displaced in the left hemisphere in boys with ASD. The SF delay in participants with ASD was present irrespective of their intelligence level and severity of autism symptoms. Limitations We did not test the language abilities of our participants. Therefore, the link between SF and processing of vocal pitch in children with ASD remains speculative. Conclusion Children with ASD demonstrate atypical processing of spectrally complex periodic sound at the level of the core auditory cortex of the left-hemisphere. The observed neural deficit may contribute to speech perception difficulties experienced by children with ASD, including their poor perception and production of linguistic prosody.
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| 3. |
- Stroganova, T. A., et al.
(författare)
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THE EFFECT OF PERIODICITY AND "VOWELNESS" OF A SOUND ON CORTICAL AUDITORY RESPONSES IN CHILDREN
- 2021
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Ingår i: Zhurnal Vysshei Nervnoi Deyatelnosti Imeni I.P. Pavlova. - 0044-4677. ; 71:4, s. 563-577
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Tidskriftsartikel (refereegranskat)abstract
- The neural basis of speech decoding is of both fundamental and practical interest for many areas of neuroscience. The discovery of highly specialized areas of the temporal cortex, which perform acoustic analysis of vowels and the pitch of spectrally complex periodic sounds, opens the way for new directions in research on speech signal processing in healthy and diseased brain. Here, we sought to dissect the effects of periodicity and "vowelness" of a sound on the neural response of the auditory cortex in typically developing children aged 7-12 years. We hypothesized that although both of these properties are pertinent to speech vowels, their processing occurs at different levels of cortical ventral auditory stream. To test this hypothesis, we constructed a set of acoustic stimuli, manipulating their periodicity and 'vowelness' separately, and used magnetoencephalography in combination with individual brain models to assess the cortical topography and temporal dynamic of cortical sources, which respond selectively to either sounds' periodicity or to their 'vowelness'. We found that the early auditory responses (50-150 ms) were highly sensitive to both periodicity and 'vowelness' of a sound, although they were separable from each other in terms of response timing, source localization and hemispheric asymmetry. Our findings suggest that the separate neural networks are independently tuned for each of these properties of the speech sound, and that transformation of the respective acoustic properties into a speech feature take place at these earliest stages in the speech processing hierarchy. Our results may help to evaluate the role of specific neural deficits in the processing of low-level properties of speech sounds in language disorders.
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