Long Latency Auditory Evoked Potentials during Meditation

Abstract

The auditory sensory pathway has been studied in meditators, using midlatency and short latency auditory evoked potentials. The present study evaluated long latency auditory evoked potentials (LLAEPs) during meditation. Sixty male participants, aged between 18 and 31 years (group mean±SD, 20.5±3.8 years), were assessed in 4 mental states based on descriptions in the traditional texts. They were (a) random thinking, (b) nonmeditative focusing, (c) meditative focusing, and (d) meditation. The order of the sessions was randomly assigned. The LLAEP components studied were P1 (40-60 ms), N1 (75-115 ms), P2 (120-180 ms), and N2 (180-280 ms). For each component, the peak amplitude and peak latency were measured from the prestimulus baseline. There was significant decrease in the peak latency of the P2 component during and after meditation (P<.001; analysis of variance and post hoc analysis with Bonferroni adjustment). The P1, P2, and N2 components showed a significant decrease in peak amplitudes during random thinking (P<.01; P<.001; P<.01, respectively) and nonmeditative focused thinking (P<.01; P<.01; P<.05, respectively). The results suggest that meditation facilitates the processing of information in the auditory association cortex, whereas the number of neurons recruited was smaller in random thinking and non-meditative focused thinking, at the level of the secondary auditory cortex, auditory association cortex and anterior cingulate cortex.

A selective review of dharana and dhyana in healthy participants

“…The next three articles which have been reviewed reported changes in short, middle and long latency evoked potentials before, during and after dharana and dhyana  [22], [23], [26].…”

“…Long-latency evoked potentials were recorded before, during and after dharana , dhyana , random thinking and focusing [26], there were 60 participants, all male, in normal health. None of them had participated in earlier studies on short latency EPs [22] or middle latency EPs [23].…”

A fMRI Study of Stages of Yoga Meditation Described in Traditional Texts

“…The difference between dharana and dhyana in using effort to direct attention is supported by data which show a shift towards vagal dominance during dhyana [10]. Apart from the autonomic variables there have been electrophysiological recordings of short [11], middle [12] and long latency [13] auditory evoked potentials during FA, MF, ME as well as during the control state (RT) of random thinking. The changes were both in the time taken for information transmission (i.e., the latency) as well as in the number of neurons recruited (indicated by the amplitude).…”

No meditation-related changes in the auditory N1 during first-time meditation

“…Similarly, the active N2 and P3 auditory ERPs, and the passive MMN ERP, increase in size in long-term meditators after meditation, and are larger in meditators compared to non-meditators (Atchley et al, 2016;Biedermann et al, 2016;Delgado-Pastor et al, 2013;Joshi and Telles, 2009;Kyizom et al, 2010;Sarang and Telles, 2006;Srinivasan and Baijal, 2007). The latencies of the active N2 and P3 peaks, and the passive P2 peaks, appear to be earlier after long-term meditators meditate (Joshi and Telles, 2009;Kyizom et al, 2010;Telles et al, 2015).…”

“…Some studies failed to include a control group, making it difficult to determine whether the ERPs were different between conditions because of the meditators' experience, or the task requirements (Barwood et al, 1978;Cahn and Polich, 2009;Chatterjee et al, 2012;Delgado-Pastor et al, 2013;Joshi and Telles, 2009;Liu et al, 1990;Sarang and Telles, 2006;Telles et al, 2015). Other studies did not include a control condition, making it difficult to determine whether the difference between groups would extend beyond a meditation task to tasks that were new to both groups (Barwood et al, 1978;Becker and Shapiro, 1981;Chatterjee et al, 2012;Joshi and Telles, 2009;Kyizom et al, 2010;Liu et al, 1990;Srinivasan and Baijal, 2007).…”