International Journal of Yoga Therapy
December 1, 2024
Shirley Telles, Sachin Kumar Sharma, Kumar Gandharva et al.
Each of five pranayama techniques changes breathing in a distinct way. In 23 yoga practitioners, high-frequency yoga breathing increased breath rate by 373.3%, while bumblebee, hissing, and alternate-nostril breathing decreased it by 75.3%, 63.0%, and 55.3%, respectively. Depth of breathing increased across all five techniques, most markedly in bumblebee (307%) and high-frequency (275%) breathing. The ratio of inspiration to expiration rose during high-frequency breathing (177%) and fell during bumblebee (74.3%) and alternate-nostril (39.0%) breathing. Breath awareness produced no changes. These results support earlier findings that high-frequency breathing is activating and enhances attention, whereas bumblebee and alternate-nostril breathing are calming and may increase vagus nerve activity.
Clinical EEG and Neuroscience
May 1, 2019
Shirley Telles, Deepeshwar Singh, K. V. Naveen et al.
Meditative focusing increased sympathetic arousal, as shown by higher low-frequency heart rate variability (HRV), lower high-frequency HRV, and a faster average heart rate. Defocused meditation decreased average heart rate. Both forms of meditation improved attention, measured by increased P300 brain-wave amplitude; defocused meditation also reduced P300 latency, meaning participants responded faster to an auditory oddball task. The findings indicate that meditation's effects on attention and sympathetic activity depend on the type of meditation practiced.
Clinical EEG and Neuroscience
October 1, 2015
Shirley Telles, Singh Deepeshwar, Kalkuni Visweswaraiah Naveen et al.
Meditation shortens the time it takes for the brain to process sounds in the auditory association cortex, as measured by a faster P2 component of long latency auditory evoked potentials. In contrast, random thinking and nonmeditative focusing reduce the number of neurons recruited in the secondary auditory cortex, auditory association cortex, and anterior cingulate cortex, shown by smaller peak amplitudes of P1, P2, and N2 components. The study assessed 60 male participants aged 18–31 years across four mental states based on traditional texts.
International journal of psychophysiology : official journal of the International Organization of Psychophysiology
November 1, 2013
Luis Carlos Delgado-Pastor, Pandelis Perakakis, Pailoor Subramanya et al.
Experienced Vipassana meditators showed greater P3b brain-wave amplitudes to target tones after a 30-minute meditation session compared with before meditation or after a no-meditation rest session, indicating increased attentional engagement. They also exhibited a larger increase in the LF/HF heart rate variability ratio during meditation, suggesting enhanced autonomic regulation. These findings partially support the idea that mindfulness, rooted in Vipassana, improves awareness of present experience and emotional self-regulation.
Clinical EEG and Neuroscience
April 1, 2012
Shirley Telles, Bhat Ramachandra Raghavendra, Kalkuni Visweswaraiah Naveen et al.
Meditation, as described in traditional yoga texts, delays auditory information transmission at the level of the medial geniculate and primary auditory cortex. In 60 participants, the Na and Pa components of mid-latency auditory evoked potentials showed prolonged latencies during meditation compared to random thinking, nonmeditative-focused thinking, and meditative focusing. Meditative focusing did not produce this effect. The findings suggest that meditation, but not mere focused attention, alters early sensory processing.
International Journal of Yoga
July 1, 2010
Sanjay Kumar, Hr Nagendra, Kv Naveen et al.
Repeating 'OM' mentally changes auditory-evoked potentials in the brainstem. Thirty experienced meditators (ages 20–55, average 29.1 years) were tested in four sessions: two control conditions (single-topic lecture and non-targeted thinking) and two meditation states (focusing on the symbol 'OM' and an effortless single-thought state of 'OM'). Wave V peak latency, indicating neural transmission at the inferior colliculus, increased significantly during non-targeted thinking, lecture, and focused meditation, but showed no change during the effortless single-thought state. This suggests that auditory information transmission is delayed in the first three conditions but not during the deeper meditative state.
International Journal of Yoga
January 1, 2010
Sanjay Kumar, Hr Nagendra, Nk Manjunath et al.
The sacred syllable Om, described in Indian scriptures as the primordial sound from which all creation emerges, signifies the Supreme Power. Drawing from four Upanisads, the Bhagavad Gita, and Patanjali's Yoga Sutras, the article examines Om's significance. Autonomic and respiratory studies suggest that mental repetition of Om produces a combination of mental alertness with physiological rest. Evoked potentials studies indicate a decrease in sensory transmission time at the level of the auditory association cortices, along with recruitment of more neurons at mesencephalic-diencephalic levels. Scientific studies suggest that Om meditation results in physiological alertness and increased sensitivity to sensory transmission.