EEG Session 24: Theta Audiovisual Entrainment

This page contains the data and analysis of a brain wave recording session I did using a Muse Gen 1 EEG Headband.

Session Characteristics

  • 09/11/2023, 20:54
  • During this session, I was testing aThetaAudiovisual Brainwave Entrainment track I created.
  • I was experiencing the track with my eyes open.

All Sensors

  • As usual,Alphadominates, but not as much as when my eyes are closed. Therefore,Alphaappears less separated from the frequencies below.
  • Thetahas second-place dominance across most of the session, however, as shown in Session 20, this is most likely due to me being in a calm state than it is a result of entrainment. So we’ll have to keep looking for clearer entrainment signs elsewhere.
  • Unlike previous tracks (which used audio only), there is a clear gradual increase ofGammaenergy over time.
  • Similarly to previous similar sessions, three distinct bands are formed —Alphaseparated on top,Gammaseparated at the bottom, and Theta,Beta,and Delta in the middle
  • However, since this session was experienced with open eyes, all these bands are closer together and grow even closer asGammaincreases in energy over time.
  • I should also note thatTheta’ssecond-place dominance is shown only in the Right hemisphere (Front-Right and Back-Right), with particular emphasis on the Back-Right.
  • Out of all similar sessions, this is the first one whereThetadoes not have second-place dominance in at least one left brain quadrant.

Right, Back Sensor (TP10, Gamma and Delta Isolated)

  • Looking at the Right, Back quadrant, very clear signs of entrainment can be found ✅
  • Specifically, in theGammafrequency range, we can find an oscillating sinusoidal pattern with sustained and consistent peaks and valleys.
  • Similar effects have been observed in some previous sessions and were initially observed in Session 19.
  • This phenomenon seems to be very prominent in this particular session and can sustain it for about four complete minutes before breaking up a bit.
  • While it occurs, we can also observe lots of phase synchronization betweenGammaandBeta(peaks and valleys align).

How Does Dominance Change Over Time?

The graphs shown below show how dominant frequencies were across the session, in %.

  • Dominance for all frequencies in the Back sensors (TP9, TP10) remained stable throughout the session.
  • The largest changes observed were in the Front sensors (AF7, AF8), namely:
  • Betaincreased steadily in dominance going from 12.5% to 26.5%, which corresponds to an increase of 112%
  • Gammaincreased steadily in dominance going from 5% to 16%, which corresponds to an increase of 220%
  • BothAlphaandThetadecreased in dominance over time.
  • Finally, I found an uncommonDeltabehavior in the Front-Left (AF7) quadrant, where this frequency range has two periods where it increases very high in dominance (sometimes up to 85% dominance) and remains there for 1 or 2 minutes. This activity is not signal noise, it didn’t occur in any other sensor, and it’s the first session where I’ve seen this behavior. At this point, I don’t know what it means, but due to its rarity and unusuality, I’m inclined to attribute this phenomenon to an effect caused by the entrainment track ✅

Absolute Average Values (All Sensors)

  • Alphaaverage: 54 dB
  • Thetaaverage: 42 dB
  • Deltaaverage: 41.7 dB
  • Betaaverage: 38 dB
  • Gammaaverage: 15 dB

Percentual Average Values (All Sensors)

  • Alphaaverage: 36%
  • Thetaaverage: 21%
  • Deltaaverage: 20%
  • Betaaverage: 16%
  • Gammaaverage: 6%

Brainwave Lateralization

Center of Gravity

For reference: the circle with the black circumference marks the central area of the brain. Activity inside it is more central and symmetrical; outside is more asymmetrical.

  • Delta’s center of gravity was located right outside the central circle border. with a pull from the Left-Back quadrant. Similar to Session 19, but with more pronounced.
  • Theta’scenter of gravity was located in the CenterRight-Back quadrant.
  • Alpha’scenter of gravity was located on the CenterRight-Back quadrant.
  • Beta’scenter of gravity starts outside the central circle, in the Center-Back quadrant, and moves towards the inside of the circle over time.
  • Gamma’scenter of gravity has a similar behavior toBeta’s,starting just outside the Center-Back border of the circle, and moving towards the central circle over time, with a deviation to the Right.
  • While not as perfect, this behavior of the faster frequencies of moving toward the circle reminds me of the very special Session 16.

Get This Track

If you are interested in trying this track, you can get it as part of the NEX: Brainwave Entrainment Bundle

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