Epileptic seizures recorded with microelectrodes: A persistent multiscale gap between neuronal activity, micro-, and...

Area of Science:

• Neuroscience
• Epilepsy Research
• Electrophysiology

Background:

• The progression of epileptic seizures from neuronal to network dynamics is poorly understood.
• Current understanding relies on macro-electrodes (macro-local field potentials/macro-LFP), with a significant gap between cellular-scale microelectrode recordings and macro-scale dynamics.
• Microelectrodes offer cellular-level insights but are often underutilized for analyzing local field potentials (micro-LFP) and bridging the micro- to macro-scale gap.

Purpose of the Study:

• To review the contribution of microelectrode recordings to understanding human epileptic seizures.
• To highlight the importance of integrating single-unit, micro-LFP, and macro-LFP data for a comprehensive synthesis of ictogenesis.
• To identify challenges and propose solutions for multiscale seizure analysis.

Main Methods:

• This narrative review synthesizes existing literature on microelectrode recordings during human epileptic seizures.
• It focuses on the analysis of micro-LFP signals and their relationship with neuronal activity and macro-LFP.
• The review discusses challenges in data acquisition, spatial correspondence, brain sampling, reference electrode reporting, recording duration, and database sharing.

Main Results:

• Microelectrode recordings provide crucial cellular-scale data (single units and micro-LFP) that are essential for understanding seizure initiation and propagation.
• A significant gap exists between micro-LFP and macro-LFP recordings, hindering a complete understanding of seizure dynamics across scales.
• Simultaneous recording and analysis of single units, micro-LFP, and macro-LFP are key to synthesizing ictal genesis.

Conclusions:

• Integrating microelectrode data with macroelectrode data is critical for a comprehensive understanding of human epileptic seizures.
• Addressing challenges in microelectrode data analysis, spatial calibration, and data sharing is necessary to advance epilepsy research.
• Future research should focus on multiscale analyses incorporating all three levels of electrophysiological recordings for a complete picture of ictogenesis.