Aug 172015
 

In previous posts, we have examined my brain waves for meditative conditions of counting and following the breath with non-meditative conditions of thinking of things and reading. Now we begin to expand the investigation to include recordings of other people. Suddenly we are faced with a host of new variables—different people may have different “baseline” brain wave patterns, they may manifest their meditation practices in different ways, and they all have different levels of experience. Each person’s brain wave patterns no doubt change throughout the day as well, based on different experiences and different expectations of the future. So it may not be possible to characterize their mental states in any simple way.

This series of recordings involved five subjects with varying meditation experience who were directed to engage their minds in meditative or non-meditative ways. Each session lasted about 20 minutes and included segments of 5-7 minutes of meditative (counting or following the breath) and non-meditative conditions (except for the second subject, S2 who sat three separate rounds of 20 minutes each).

The charts below show results from subject S3 who was asked to meditate by counting her breath for seven minutes, then start worrying about something for the next seven minutes, then return to meditating by following her breath for the final seven minutes. She chose to worry about work.

If you hover the mouse over each chart, you should see comments made by the subject immediately after the recording session. Click on a chart to see it full-size.

Counting the breath Worrying about work Following the breath
 S3-following-breath-1-rec66  S3-worrying-2-rec66  S3-following-breath-3-rec66

We see a fairly dramatic increase in the relative power of delta band frequencies, which may be associated with the feeling of “panic” the subject describes when she is worrying about work. This subject, S3 has about 400 hours of meditation experience.

The next two subjects chose a non-meditative condition of thinking about people they know and relationships they have had.

Following the breath Thinking of people Counting the breath
 S2-following-breath-rec86  S2-thinking-of-people-rec86  S2-counting-breaths-rec86

Subject S2 exhibits a smaller fraction of delta power than subject S3 while counting her breath. In the second segment, when thinking about people the fractions of beta and gamma power go up, then return to a meditative pattern similar to the first segment. S2 has had about 500 hours of meditation experience.

Counting the breath Thinking of people Counting the breath
S4-following-breath-1-rec67  S4-thinking-of-people-2-rec67  S4-following-breath-3-rec67

Subject S4 chose to meditate, then think of people, then return to meditating. S4 has about 500 hours of meditation experience. She exhibits a larger fraction of delta power when thinking of people than she does in the first segment of counting her breath. Also, her pattern of strong delta power in the second segment is quite different from subject S2 for a similar condition (thinking of people).

Worrying about work Following the breath  Worrying about work
 S13-worrying-1-rec69  S13-meditating-rec69  S13-worrying-3-rec69

Subject S13 chose to begin with a 7-minute segment of worrying, then meditate by following the breath, then return to worrying. The worrying segments are characterized by stronger delta rhythm while the meditation segment has brought in more beta and gamma. Subject S13 has about 900 hours of meditation experience.

Worrying about work Counting the breath Worrying about work Counting the breath
 S5-worrying-1-rec70  S5-zazen-2-rec70  S5-worrying-3-rec70  S5-zazen-4-rec70

Subject S5 is a highly trained Zen practitioner, with over 18,000 hours of experience. He was asked to start by worrying about work for 7 minutes, then do zazen for 7 minutes, return to worrying for 7 minutes and end with 7 minutes of zazen. The predominant EEG power is in the delta, beta and gamma bands. Interestingly, the change in pattern from worrying to zazen and back is relatively minor. At least compared to the other subjects above, he exhibits less change in EEG pattern whether he is meditating or not.

  2 Responses to “Other’s brain wave patterns for meditative and non-meditative conditions”

  1. Hello,
    Fascinating blog you have. I don’t posess the tech knowledge to understand everything here, and one thing seems very confusing to me : In your tests , Delta waves seems associated with anxiety and panic, while meditative states are associated with Beta and Gamma. Shouldn’t it be the other way around ? Everything I’ve read points to high Gamma and Beta being associated with intense activity bordering on panic attacks, while Delta is usually deep sleep, and Alpha is conscious relaxed sleep.

    • Excellent question, Al.

      I too was surprised to see what looked like strong delta waves for a subject who was worrying, since delta is associated with deep sleep. But when I plotted eye blinks, I found that when worrying, she was also blinking her eyes frequently. The electrical impulses arising from muscle activity in the eyes could easily be oscillations that masquerade as delta waves in the cortex.

      Yes, beta activity is often associated with “associated with active, busy, or anxious thinking and active concentration” [Wikipedia]. I’m seeing it during meditation, so perhaps this is more an indication of focused concentration than relaxation.

      Regarding gamma frequencies, check out the work of Richard Davidson at the University of Wisconsin, Madison. See for example,
      https://www.youtube.com/watch?v=DyhFLtXZexU

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