Abnormally diffuse pattern of visual gamma coherence in children with Autism Spectrum Disorder (ASD)статья
Статья опубликована в высокорейтинговом журнале
Информация о цитировании статьи получена из
Web of Science
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 4 мая 2020 г.
Аннотация:Background: Aberrant local and global brain connectivity patterns have been hypothesized as a key neural underpinning of autism, but how these abnormalities manifest itself in different functional domains is far from clear. In this study, visual gamma oscillations induced in primary visual cortex by moving circular gratings were used to explore the putatively functionally abnormal local visual networks in children with ASD. Given that even remote cerebral cortical areas may synchronize in the gamma frequency range with the zero time lag (Vicente et al, 2008), we expected that gamma coherence measure that is sensitive to both ‘phase-lagged’ and ‘zero-phase-lagged’ connectivity may provide valuable information on synchronization properties of visual cortical network.
Methods: MEG data were acquired from in ASD (n = 27) and typically developing (n = 28) children 7–15 years old, while the participants were watching the circular black and white grating drifting toward the center of the stimulus display at velocity of 1.6 cps. The sensor-level analysis was focused on stimulus-induced changes in spectral power and coherence during the sustained phase of gamma response (400 – 1000 ms after the stimulus onset). Pair-wise coherence was computed between two occipital midline planar gradiometers that demonstrated greatest stimulus-related growth of the gamma power on the group level and all the other planar gradiometers from posterior sensor selection. Nonparametric permutation tests were conducted and corrected for multiple comparisons.
Results: Both groups demonstrated highly significant sustained gamma response centered around 60 Hz, with topographical maxima at midline occipital MEG sensors. The response strength was significantly reduced in ASD compared to TD subjects (p < 0.05 FWE corrected). The reliable frequency-specific increase in gamma coherence (relative to the pre-stimulus baseline) was restricted to a few pairs of sensors in the TD group while the ASD group had a diffuse pattern of increased gamma coherence across the whole posterior sensor array. The direct between-group comparison confirmed presence of the ASD-TD difference in the topographical pattern of gamma coherence (F(1,53) = 6.07, p < 0.02 for mean coherence increase). The opposite trends in ASD-TD difference in the stimulus-induced changes of gamma coherence and power refute the possibility that the coherence differences are explained by the magnetic field spread.
Conclusion: The finding of abnormally widespread gamma coherence induced by visual stimulation in children with ASD points to the reduced visual network differentiation and “noisy” crosstalk between multiple cortical areas.
The study has been supported by Russian Science Foundation grant #14-35-00060.