Time-Frequency Analysis for EEG/MEG Explained! | Neuroscience Methods 101

Time-frequency analysis is a way to analyze signals from electroencephalography (EEG) and magnetoencephalography (MEG). But how does it work?

In a time-frequency analysis a brain waves are analyzed. The brain signals we pick up with EEG reflect group level activity of neurons below the sensor. This activity is often oscillatory. These brain oscillations have different functions depending on their frequency. As such, we would like to see how brain oscillation frequency changes over time and how it changes when we are doing a task. In that case we look at event-related oscillations (ERO)

With time-frequency analysis we can look at evoked activity, which is when a phase reset of the oscillation occurs. In this case event-related oscillation is often similar to the event-related potential (ERP), which is the EEG signal in the time (temporal) domain. Indeed, EROs are expressed in the frequency domain.

We can also look at induced activity, where a change in brain oscillation power is not associated with a phase reset. ERPs will often look flat, because the signals cancel each other out. However, time frequency analysis will still show a clear response.

References:
Adjamian P. (2014). The application of electro- and magneto-encephalography in tinnitus research - methods and interpretations. Frontiers in neurology, 5, 228. https://doi.org/10.3389/fneur.2014.00228

David, O., Kilner, J. M., & Friston, K. J. (2006). Mechanisms of evoked and induced responses in MEG/EEG. NeuroImage, 31(4), 1580–1591. https://doi.org/10.1016/j.neuroimage....

Herrmann, C. S., & Knight, R. T. (2001). Mechanisms of human attention: event-related potentials and oscillations. Neuroscience and biobehavioral reviews, 25(6), 465–476. https://doi.org/10.1016/s0149-7634(01...

Herrmann, C. S., Rach, S., Vosskuhl, J., & Strüber, D. (2014). Time-frequency analysis of event-related potentials: a brief tutorial. Brain topography, 27(4), 438–450. https://doi.org/10.1007/s10548-013-03...

Magazzini, L., & Singh, K. D. (2018). Spatial attention modulates visual gamma oscillations across the human ventral stream. NeuroImage, 166, 219–229. https://doi.org/10.1016/j.neuroimage....

Rosenblum, Y., Shiner, T., Bregman, N., Fahoum, F., Giladi, N., Maidan, I., & Mirelman, A. (2022). Event-related oscillations differentiate between cognitive, motor and visual impairments. Journal of neurology, 269(7), 3529–3540. https://doi.org/10.1007/s00415-021-10...

Wischnewski, M., & Schutter, D. J. L. G. (2019). Electrophysiological correlates of prediction formation in anticipation of reward- and punishment-related feedback signals. Psychophysiology, 56(8), e13379. https://doi.org/10.1111/psyp.13379

Narrated by: Miles Wischnewski

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