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Periodic and aperiodic changes to cortical EEG in response to pharmacological manipulation

  • 0Department of Psychiatry, Washington University in St. Louis School of Medicine, St. Louis, Missouri, United States.
Journal of Neurophysiology +

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February 7, 2024

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February 7, 2024

View abstract on PubMed

Summary

This summary is machine-generated.

The aperiodic exponent of electroencephalograms (EEGs) is not a reliable marker for the brain's excitation/inhibition balance. This study found inconsistencies with pharmacological manipulations, indicating a need for alternative biomarkers in neuropsychiatric research.

Area Of Science

  • Neuroscience
  • Computational Neuroscience
  • Pharmacology

Background

  • Cortical electroencephalograms (EEGs) offer insights into neuropsychiatric disorders and treatment mechanisms.
  • The aperiodic component (1/f) of EEG power spectra, often considered noise, may reflect the excitation/inhibition balance.
  • Previous studies are confounded by behavioral state, necessitating robust validation of EEG parameters.

Purpose Of The Study

  • To rigorously test the aperiodic exponent of EEG power spectra as a reliable indicator of cortical excitation/inhibition balance.
  • To investigate the impact of specific pharmacological manipulations on the aperiodic exponent.
  • To determine if the aperiodic exponent can serve as a universal biomarker for excitation/inhibition ratio.

Main Methods

  • Analysis of video-EEG data from mice during active exploration.
  • Application of the fitting oscillations and one over f (FOOOF) algorithm to EEG power spectra.
  • Pharmacological interventions including GABA<sub>A</sub> receptor modulators, ketamine, GABA<sub>A</sub>R antagonists, and Designer Receptors Exclusively Activated by Designer Drugs (DREADDs) to manipulate neuronal activity.

Main Results

  • GABA<sub>A</sub> receptor-positive allosteric modulators increased the aperiodic exponent, aligning with the hypothesis of enhanced cortical inhibition.
  • Ketamine and GABA<sub>A</sub>R antagonists did not produce predicted changes in the aperiodic exponent.
  • Suppression of parvalbumin-positive interneurons using DREADDs unexpectedly increased the aperiodic exponent, contradicting the expected outcome.

Conclusions

  • The aperiodic exponent of EEG power spectra is not a universally reliable marker for cortical excitation/inhibition ratio.
  • Observed inconsistencies suggest that other factors influence the aperiodic exponent beyond excitation/inhibition balance.
  • Further research is required to identify dependable biomarkers for excitation/inhibition balance in neuropsychiatric conditions.

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