Related Experiment Video
Updated: Dec 25, 2025
12:03
A Method for Tracking the Time Evolution of Steady-State Evoked Potentials
Published on: May 25, 2019
8.8K
The shaky ground truth of real-time phase estimation
Christoph Zrenner1, Dragana Galevska1, Jaakko O Nieminen2
1Department of Neurology & Stroke, And Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany.
Neuroimage
|March 22, 2020
Summary
Accurately estimating brain oscillation phase from electroencephalography (EEG) is crucial for understanding brain states. This study defines conditions for reliable pre-stimulus phase estimation, enabling causal analysis of brain activity.
Area of Science:
- Neuroscience
- Signal Processing
- Computational Biology
Background:
- Instantaneous phase in electroencephalography (EEG) reflects brain state and influences neural processing.
- Standard methods struggle to determine phase at stimulus onset due to artifact interference.
- Accurate phase estimation is vital for understanding stimulus-evoked responses and brain dynamics.
Purpose of the Study:
- To quantify the impact of signal-to-noise ratio (SNR) and instantaneous amplitude on EEG phase estimation error.
- To define experimental conditions for reliable causal phase estimation.
- To provide tools and a workflow for optimizing and benchmarking phase estimation algorithms.
Main Methods:
- Analysis of phase estimation error variance using equivalent estimators.
- Simulation of realistic EEG data with known synthetic phase.
- Development and validation of a causal phase estimation toolbox using pre-stimulus EEG data.
Main Results:
- Established the relationship between SNR, instantaneous amplitude, and phase estimation precision.
- Specified conditions under which pre-stimulus phase estimation is meaningful.
- Demonstrated modulation of corticospinal excitability by pre-stimulus sensorimotor rhythm phase using transcranial magnetic stimulation (TMS).
Conclusions:
- Causal phase estimation in EEG is feasible under specific signal conditions.
- The developed toolbox and workflow facilitate accurate analysis of brain states.
- Pre-stimulus EEG phase significantly modulates neural excitability, offering insights into brain function.
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