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Perinatal asphyxia impact on networks of cortical activity

Pediatric Research (2024)Cite this article

The study by Syvälahti et al.1 demonstrates that EEG connectivity provides valuable insights into the brain’s electrical activity and connectivity patterns in hypoxic-ischemic brain injury. In this study, the severity of brain injury within the first day of life categorized infants with perinatal asphyxia into three subgroups: 29 without HIE (PA), 10 with mild HIE (HIE1), and 12 with moderate HIE (HIE2). Electroencephalograms (EEG) were recorded using 19 scalp electrodes, supplemented by polygraph electrodes for vigilance state detection. The EEG signals were filtered into five bands of interest: Low delta (δ1) 0.4–1.5 Hz, high delta (δ2) 1.5–4 Hz, theta (θ) 4–8 Hz, alpha (α) 8–13 Hz, and beta (β) 13–22 Hz. Quiet sleep (QS) EEGs were characterized by high-voltage, low-frequency activity, or tracé alternat, with regular respiration. In this study, the analysis delved into five essential aspects of brain EEG activity:

  1. 1.

    Frequency-specific amplitudes: This measure of oscillatory activity is calculated as the mean amplitudes of envelopes averaged over electrodes for each frequency band.

  2. 2.

    Activation synchrony index (ASI): It quantifies the interhemispheric co-occurrence of burst activity between two electrodes, providing a measure of synchrony between the left and right hemispheres of the brain.

  3. 3.

    Phase-phase correlations (PPCs) PPCs reveal the synchronized timing of brain activity between regions, indicating coordinated activation patterns.

  4. 4.

    Amplitude-amplitude correlations (AACs): how similar the overall strength of brain activity is between regions, suggesting co-modulation of cortical activity across the brain.

  5. 5.

    Phase amplitude correlations (PACs): These were employed to explore cross-frequency interactions between the phase of low-frequency (nesting) oscillations (delta) and the phase of amplitude envelope of high-frequency (nested) oscillations (theta, alpha, beta) for each electrode and then at a global measure.

Frequency-specific amplitudes: This measure of oscillatory activity is calculated as the mean amplitudes of envelopes averaged over electrodes for each frequency band.

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Data availability

Data availability is not applicable to this article, as no new datasets were generated or analyzed during the current study.

References

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Funding

This study is supported by Award Number R01 NS102617 from NIH National Institute of Neurological Disorders and Stroke to Dr. Chalak.

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  1. Division of Neonatal-Perinatal Medicine, Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, USA

    Srinivas Kota & Lina Chalak

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  1. Srinivas Kota
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  2. Lina Chalak
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Correspondence to Lina Chalak.

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Kota, S., Chalak, L. Perinatal asphyxia impact on networks of cortical activity. Pediatr Res (2024). https://doi.org/10.1038/s41390-024-03085-8

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