A single case design to examine short-term intracranial EEG patterns during focused meditation

Influence of mindfulness meditation on intracranial EEG parameters in epileptic and non-epileptic brain areas

OBJECTIVE

Mind-wandering is a pervasive human brain state and, when in excess, may promote negative affect and neuropsychiatric conditions. Mindfulness meditation may promote alternate brain states, improving affect and reducing stress. An understanding of the neural basis between these brain states could thus advance treatment of neuropsychiatric conditions, including those associated with epilepsy.

METHODS

To explore the neural basis of mindfulness meditation versus mind-wandering, we enrolled eight patients in a trial of structured mindfulness meditation and open mind-wandering who underwent stereo electroencephalography (sEEG) within the mesial temporal lobe for seizure localization. Electrophysiology was compared between mind-wandering and mindfulness separately for epileptic and non-epileptic MTL. Using fitting-one-over-f modeling, periodic components of electrophysiology were compared in canonical frequency bands of theta (4-8 Hz), alpha (8-13 Hz), beta (13-30 Hz), and gamma (30-55 Hz). Aperiodic components of the power spectra were assessed by the model offset, knee, and exponent.

RESULTS

We found a significant reduction in gamma power (30-55 Hz) within the mesial temporal lobe (MTL) during mindfulness meditation compared with mind-wandering in non-epileptic (p = 1.20E-4) but not in epileptic MTL (p = 0.352).There was also a significant difference between epileptic versus non-epileptic MTL in gamma power between conditions (p = 0.011). There were no significant changes in power across any frequency band within epileptic mesial temporal MTL between brain states. Conversely, there were significant differences between mind-wandering and mindfulness within epileptic MTL in aperiodic components (offset, knee, and exponent, all p < 0.05), while no differences in aperiodic components were seen in non-epileptic MTL (all p > 0.70).

SIGNIFICANCE

Intracranial electrophysiologic modulations between brain state (mind-wandering versus mindfulness) may differ between epileptic and non-epileptic MTL. Modulations in gamma activity in non-epileptic MTL may represent functional changes in brain state, while aperiodic changes in epileptic MTL may modulate propensity for seizures.

EEG brain oscillations are modulated by interoception in response to a synchronized motor vs. cognitive task

So far, little is known about how conscious attention to internal body signals, that is, interoception, affects the synchronization with another person, a necessary or required social process that promotes affiliations and cooperation during daily joint social interactions. The effect of explicit interoceptive attentiveness (IA) modulation, conceived as the focus on the breath for a given time interval, on electrophysiological (EEG) correlates during an interpersonal motor task compared with a cognitive synchronization task was investigated in this study. A total of 28 healthy participants performed a motor and a cognitive synchronization task during the focus and no-focus breath conditions. During the tasks, frequency bands (delta, theta, alpha, and beta bands) from the frontal, temporo-central, and parieto-occipital regions of interest (ROIs) were acquired. According to the results, significantly higher delta and theta power were found in the focus condition in the frontal ROI during the execution of the motor than the cognitive synchronization task. Moreover, in the same experimental condition, delta and beta band power increased in the temporo-central ROI. The current study suggested two main patterns of frequency band modulation during the execution of a motor compared with the cognitive synchronization task while a person is focusing the attention on one's breath. This study can be considered as the first attempt to classify the different effects of interoceptive manipulation on motor and cognitive synchronization tasks using neurophysiological measures.

Neural dynamics of mindfulness meditation and hypnosis explored with intracranial EEG: A feasibility study

PURPOSE

Intracranial electroencephalography (iEEG) offers a unique window on brain dynamics with excellent temporal and spatial resolution and is less prone to recording artefacts than surface EEG. This study used a within-subject design to explore the feasibility to compare iEEG data during mind wandering, mindfulness meditation and hypnosis.

RESULTS

Three patients who had iEEG for clinical monitoring and who were new to mindfulness meditation and hypnosis were able to enter these states. We found non-specific and wide-spread amplitude modulations. Data-driven connectivity analysis revealed widespread connectivity patterns that were common across the three conditions. These were predominant in the low frequencies (delta, theta and alpha) and characterised by positively correlated activity. Connectivity patterns that were unique to the three conditions predominated in the gamma band, one third of the correlations in these patterns were negative.

CONCLUSIONS

This study is the first to support the feasibility of a direct comparison of the neural correlates of mindfulness meditation and hypnosis using iEEG. These modulations may reflect the complex interplay between different known brain networks, and warrant further functional investigations in particular in the gamma band.

The effects of an internet-based mindfulness meditation intervention on electrophysiological markers of attention

Evidence suggests that mindfulness meditation training has the potential to train aspects of attention. However, the neurophysiological mechanisms underpinning the attentional benefits from mindfulness remain unclear. This randomized controlled trial examined changes in electrophysiological markers of attention before and after completion of a 6-week internet-based mindfulness intervention. EEG and ERP data were collected from 64 generally healthy, mildly stressed older adults. Participants were randomized to an internet-based mindfulness-based stress reduction course (IMMI), an internet-based health and wellness education course, or a waitlist control condition. Attentional N2 and P3 evoked potentials were derived from active and passive auditory oddball paradigms. Participants in the IMMI group showed significantly greater differences in P3 peak-trough amplitude between the active and passive oddball paradigms at endpoint relative to controls. There were no significant relationships between the intervention and N2 potentials. Our data demonstrate a measurable increase in attentional control when discriminating or directing attention away from auditory stimuli for older adult participants who received mindfulness training. These findings lend support to the use of the P3 as a neurophysiological measure of meditation engagement and intervention efficacy.