Respiratory modulations of cortical excitability and interictal spike timing in focal epilepsy: a case report

Commun Med (Lond). 2025 Apr 10;5(1):108. doi: 10.1038/s43856-025-00811-z.

Abstract

Background: Brain activity in focal epilepsy is marked by a pronounced excitation-inhibition (E:I) imbalance and interictal epileptiform discharges (IEDs) observed in periods between recurrent seizures. As a marker of E:I balance, aperiodic neural activity and its underlying 1/f characteristic reflect the dynamic interplay of excitatory and inhibitory currents. Recent studies have independently assessed 1/f changes both in epilepsy and in the context of body-brain interactions in neurotypical individuals where the respiratory rhythm has emerged as a potential modulator of excitability states in the brain.

Methods: Here, we investigate respiration phase-locked modulations of E:I balance and their involvement in the timing of spike discharges in a case report of a 25 year-old focal epilepsy patient using magnetoencephalography (MEG).

Results: We show that i) respiration differentially modulates E:I balance in focal epilepsy compared to N = 40 neurotypical controls and ii) IED timing depends on both excitability and respiratory states.

Conclusions: These findings overall suggest an intricate interplay of respiration phase-locked changes in excitation and the consequential susceptibility for IED generation and we hope they will spark interest in subsequent work on body-brain coupling and E:I balance in epilepsy.

Plain language summary

Epilepsy is a brain disorder in which abnormal electrical activity in the brain leads to seizures. We investigated the impact of breathing on electrical activity, particularly how breathing influences the balance between excitation and inhibition of electrical activity in the brain. We compared the impact of breathing patterns in a 25-year-old epilepsy patient on the excitation-inhibition balance with the effects seen in healthy individuals. We found there was a relationship between breathing and brain activity in the patient with epilepsy. We recommend further research be undertaken on how bodily rhythms impact epilepsy management, including the balance between excitation and inhibition in the brain.