Temporal dynamics of electroconvulsive therapy induced seizures

Area of Science:

• Neuroscience
• Computational Psychiatry
• Medical Physics

Background:

• Electroconvulsive therapy (ECT) is a vital treatment for severe psychiatric conditions.
• The cortex and thalamus play crucial roles in the generation and cessation of seizures.
• Understanding the spatiotemporal dynamics of ECT-induced seizures is key to optimizing treatment.

Purpose of the Study:

• To investigate the spatiotemporal dynamics of electroencephalogram (EEG) features during ECT-induced seizures.
• To model the underlying biophysical parameters, including cortical excitation/inhibition (E/I) balance and corticothalamic loop strengths.
• To correlate EEG dynamics with model parameters throughout seizure progression.

Main Methods:

• Analysis of 345 ictal EEGs from 33 patients undergoing ECT.
• Quantification of EEG features: dominant frequency, temporal, and spatial correlations.
• Application of a corticothalamic biophysical model to assess E/I balance and loop strengths.
• Tracking the temporal evolution of EEG features and model parameters from seizure onset to termination.

Main Results:

• ECT-induced seizures exhibited EEG slowing and increased temporal correlations nearing termination.
• Cortical E/I ratios and corticothalamic loop strength increased, while intrathalamic strength decreased.
• EEG slowing and temporal correlation increases correlated with higher cortical E/I ratios and reduced intrathalamic loop strength.

Conclusions:

• ECT-induced seizures display distinct temporal dynamics characterized by slowing and increased correlations.
• These dynamics are potentially driven by an increased cortical E/I ratio and diminished intrathalamic loop strength.
• The study highlights characteristic temporal corticothalamic dynamics during ECT seizures.