Peter Malinowski

Mind wandering refers to spontaneous shifts of attention from ongoing tasks to unrelated thoughts. Evidence shows that such shifts are characterized by behavioral and physiological changes, such as heart rate and eye blinks. However, previous findings on cardiac changes during mind wandering are mixed, and little is known about whether mindfulness experience and acceptance-related traits are associated with distinct psychophysiological responses to mind wandering. To shed light on this topic, we investigated psychophysiological correlates of mind wandering in 26 experienced meditators and 24 non-meditating controls during a Sustained Attention to Response Task (SART) with thought probes. We recorded heart rate and eye blinks; mindfulness-related traits and mind wandering phenomenology were assessed through questionnaires. Results showed that, while mind wandering episodes were associated with more frequent eye blinks and slower reaction times in both groups, between-group differences emerged for heart rate. Indeed, only meditators showed a significant heart rate reduction during mind wandering, whereas controls did not. In addition, individual heart rate differences between mind wandering and on-task SART episodes were associated with self-reported levels of experiential acceptance. Overall, meditators reported higher levels of experiential acceptance and assessed their mind wandering episodes as more realistic and concrete than controls. These findings contribute to the literature by showing that, while eye blinks and reaction times may reflect the general attentional cost of mind wandering, heart rate may be more sensitive to individual differences in how these episodes are experienced and regulated, particularly in relation to meditation experience and experiential acceptance.

Objectives: The main objective of the present study was to explore the effects of different types of meditation on the neurophysiologic mechanisms of pain processing. Method: EEG responses to electric median nerve stimulation were recorded in short-term and long-term meditators (STM, LTM) during rest and three forms of meditation engaging attentional and affective regulation in different ways: focused attention meditation (FAM), open monitoring meditation (OMM), and loving-kindness meditation (LKM). EEG responses were analysed in the time- and time-frequency domains to compute local components, and temporal and spatial synchronizations of multi-spectral pain-related oscillations (PROs) in order to characterize bottom-up processes, proactive modulation of cortical excitability, cognitive/affective appraisal, and the connectivity of performance monitoring (fronto-medial) and attentional (fronto-parietal) networks during pain processing. Results: STM manifested a significant decrease in the connectedness of the fronto-medial theta-alpha network and a significant reduction of the P3b during LKM. In contrast, changes in LTM were observed during FAM and OMM. They were characterized by pre-stimulus alpha increase at somatosensory areas, and modulations of fronto-medial and fronto-parietal theta-alpha synchronizations. Conclusions: Different meditation states do not influence bottom-up sensory pain processing. However, they significantly alter cognitive/affective pain mechanisms in state- and trait-dependent ways. In novice meditators, a positive emotional disposition during meditation can suppress the distribution and cognitive/affective appraisal of nociceptive signals. In expert meditators, the effects of meditation states on pain processing are critically guided by advanced control of internal attention leading to fine-tuned involvement and functional segregation of cognitive control and attention networks. Preregistration: This study is not preregistered.

The objective of the present study was to characterize the effects of long-term meditation (LTM) on directed connectivity patterns during resting-state and meditative brain states. Specifically, it was aimed to identify major cortical sources of information flow and target regions of information influx, and to reveal which frequency-specific oscillatory networks are critically involved in directing information flux in experienced meditators. Multivariate Granger causality (GC) was computed from high-resolution EEG signals recorded from long-term (LTM, n = 22) and short-term meditators (STM, n = 17) in four conditions: rest, Focused Attention Meditation, Open Monitoring Meditation, and Loving Kindness Meditation. GC was analyzed in the time and frequency domains to assess frequency-specific networks supporting the directed connectivity between key cortical regions (frontal and parietal) in the two hemispheres. According to the results, long-practice meditation was characterized by a significant increase of information flow (1) from posterior to frontal cortical regions, and (2) across frontal regions of the two hemispheres. These dominant transfers were supported by multi-spectral oscillatory networks involving theta, alpha and beta frequency bands, with most prominent expression of GC alpha peak. This pattern of enhanced information transfer in LTM relative to STM was observed in both resting state and each meditation state. These results suggest that long-term meditation is associated with a shift in resting-state brain dynamics toward reduced reliance on slow, undirected intrinsic oscillations, and enhanced directional connectivity in frequencies linked to attention and cognitive control. The dominant posterior-to-anterior directionality points to a reorganization of cognitive control networks that may support the phenomenological qualities of extensive meditation (sustained attention, internal attention, present-moment awareness, and reduced cognitive elaboration). The similarity of between-group differences in directionality patterns across states points to a neuroplastic effect of long-term meditation and highlights meditation as a potential model for investigating adaptive neuroplasticity in large-scale brain networks.

The present study applied spectral Granger causality analysis to electroencephalographic (EEG) recordings obtained during Focused Attention Meditation (FAM), Open Monitoring Meditation (OMM), and Loving Kindness Meditation (LKM) in highly experienced meditators. The aim of the investigation was to uncover distinct connectivity signatures associated with each meditation style by examining the strength, frequency band, and direction of inter-regional information transfers. These differences were expected to highlight the neural grounds of the cognitive and affective state of each meditative practice. Multivariate Granger causality (GC) was computed from high-resolution EEG signals recorded from long-term meditators (n = 22) in four conditions: rest, FAM, OMM, and LKM. GC was analyzed in the frequency domain for key cortical regions (frontal and parietal) in the two hemispheres to compare frequency-specific directed connectivity between rest and each meditation type. Main results demonstrated that each meditation state produced highly specific alterations in information transfer relative to rest. In FAM, there was significant reduction in posterior-to-anterior GC in the alpha and beta bands, and decreased multi-spectral inter-hemispheric frontal GC pointing to attenuated bottom-up sensory and associative inputs. In OMM, multi-spectral GC was significantly increased from the left hemisphere to the right posterior cortex implying expanded awareness in the right posterior regions through enhanced top-down modulation by the left-hemisphere. The distinctive features of LKM profile were the inter-hemispheric symmetry, the posterior-anterior bi-directionality, and the specific beta-band engagement, implying a co-activation of systems that support an emotionally balanced stance, equanimity and pro-social attitude. These novel findings demonstrate that the direction and frequency specificity of information flows provide complementary insights into neural processes underlying distinct meditative states.

Objectives The main objective of the present study was to explore the effects of different types of meditation on the neurophysiologic mechanisms of pain processing. Methods EEG responses to electric median nerve stimulation were recorded in short-term and long-term meditators (STM, LTM) during rest and three forms of meditation engaging attentional and affective regulation in different ways: focused attention meditation (FAM), open monitoring meditation (OMM) and loving kindness meditation (LKM). EEG responses were analysed in the time- and time-frequency domains to compute local components, and temporal and spatial synchronizations of multi-spectral pain-related oscillations (PROs) in order to characterize bottom-up processes, pro-active modulation of cortical excitability, cognitive/affective appraisal, and the connectivity of performance monitoring (fronto-medial) and attentional (fronto-parietal) networks during pain processing. Results STM manifested a significant decrease in the connectedness of the fronto-medial theta-alpha network and a significant reduction of the P3b during LKM. In contrast, changes in LTM were observed during FAM and OMM. They were characterized by pre-stimulus alpha increase at somatosensory areas, and modulations of fronto-medial and fronto-parietal theta-alpha synchronizations. Conclusions Different meditation states do not influence bottom-up sensory pain processing. However, they significantly alter cognitive/affective pain mechanisms in state- and trait-dependent ways. In novice meditators, a positive emotional disposition during meditation can suppress the distribution and cognitive/affective appraisal of nociceptive signals. In expert meditators, effects of meditation states on pain processing are critically guided by advanced control of internal attention leading to fine-tuned involvement and functional segregation of cognitive control and attention networks.

Pure presence (PP) is described in several meditative traditions as an experience of a vast, vivid luminosity devoid of perceptual objects, thoughts, and self. Integrated information theory (IIT) predicts that such vivid experiences may occur when the substrate of consciousness in the cerebral cortex is virtually silent. To assess this prediction, we recorded 256-electrode high-density electroencephalography (hdEEG) in long-term meditators of Vajrayana and Zen traditions who were able to reach PP towards the end of a retreat. Because neural activity is typically associated with increased EEG gamma power, we predicted that PP should be characterized by widespread gamma decreases. For meditators of both traditions, PP was associated with decreased broadband hdEEG power compared to within-meditation mind-wandering, most consistent in the gamma range (30–45 Hz). Source reconstruction indicated that gamma decrease was widespread but especially pronounced in posteromedial cortex. PP broadband power also decreased compared to all other control conditions, such as watching or imagining a movie, active thinking, and open-monitoring. PP delta power (1–4Hz) was also markedly decreased compared to dreamless sleep. PP with minimal perceptual contents or accompanied by a feeling of bliss showed hdEEG signatures close to PP. In contrast, gamma activity increased during phases characterized by rich perceptual contents, such as visualization or mantra recitation. Overall, these results are consistent with PP being a state of vivid consciousness during which the cerebral cortex is highly awake (decreased delta activity) but neural activity is broadly reduced (decreased gamma activity), in line with IIT’s predictions. Significance Statement Pure presence (PP) is described in several meditative traditions as an experience of a vast, vivid luminosity devoid of perceptual objects, thoughts, and self. Integrated information theory (IIT) predicts that such vivid experiences may occur when the substrate of consciousness in the cerebral cortex is virtually silent. We recorded 256-electrode high-density electroencephalography (hdEEG) in Vajrayana and Zen long-term meditators who could reach PP towards the end of a retreat. Compared to all control conditions, PP was characterized by decreased broadband hdEEG power, most consistent in the gamma range. These results are consistent with PP being a state of vivid consciousness during which the cerebral cortex is highly awake but neural activity is broadly reduced, in line with IIT’s predictions.

Meditation practice is suggested to engage training of cognitive control systems in the brain. To evaluate the functional involvement of attentional and cognitive monitoring processes during meditation, the present study analysed the electroencephalographic synchronization of fronto-parietal (FP) and medial-frontal (MF) brain networks in highly experienced meditators during different meditation states (focused attention, open monitoring and loving kindness meditation). The aim was to assess whether and how the connectivity patterns of FP and MF networks are modulated by meditation style and expertise. Compared to novice meditators, (1) highly experienced meditators exhibited a strong theta synchronization of both FP and MF networks in left parietal regions in all mediation styles, and (2) only the connectivity of lateralized beta MF networks differentiated meditation styles. The connectivity of intra-hemispheric theta FP networks depended non-linearly on meditation expertise, with opposite expertise-dependent patterns found in the left and the right hemisphere. In contrast, inter-hemispheric FP connectivity in faster frequency bands (fast alpha and beta) increased linearly as a function of expertise. The results confirm that executive control systems play a major role in maintaining states of meditation. The distinctive lateralized involvement of FP and MF networks appears to represent a major functional mechanism that supports both generic and style-specific meditation states. The observed expertise-dependent effects suggest that functional plasticity within executive control networks may underpin the emergence of unique meditation states in expert meditators.

Meditation has been integrated into different therapeutic interventions. To inform the evidence-based selection of specific meditation types it is crucial to understand the neural processes associated with different meditation practices. Here we explore commonalities and differences in electroencephalographic oscillatory spatial synchronisation patterns across three important meditation types. Highly experienced meditators engaged in focused attention, open monitoring, and loving kindness meditation. Improving on previous research, our approach avoids comparisons between groups that limited previous findings, while ensuring that the meditation states are reliably established. Employing a novel measure of neural coupling – the imaginary part of EEG coherence – the study revealed that all meditation conditions displayed a common connectivity pattern that is characterised by increased connectivity of (a) broadly distributed delta networks, (b) left-hemispheric theta networks with a local integrating posterior focus, and (c) right-hemispheric alpha networks, with a local integrating parieto-occipital focus. Furthermore, each meditation state also expressed specific synchronisation patterns differentially recruiting left- or right-lateralised beta networks. These observations provide evidence that in addition to global patterns, frequency-specific inter-hemispheric asymmetry is one major feature of meditation, and that mental processes specific to each meditation type are also supported by lateralised networks from fast-frequency bands.

The sense of touch is primarily considered a discriminative and exteroceptive sense, facilitating the detection, manipulation and exploration of objects, via an array of low‐threshold mechanoreceptors and fast conducting A‐beta (Aβ) afferents. However, a class of unmyelinated, low‐threshold mechanoreceptors identified in the hairy skin of mammals have been proposed to constitute a second, anatomically distinct system coding the affective qualities of touch. Unlike Aβs, which increase their firing rate linearly with the velocity of a stimulus moving across their receptive field, the response of these C‐tactile afferents (CTs) is described by an inverted ‘U’ curve fit, responding optimally to a skin temperature stimulus moving at between 1 and 10 cm/s. Given the distinct velocity tuning of these fast and slow touch fibres, here we used event‐related potentials to compare the time course of neural responses to 1st (fast) and 2nd (slow) touch systems. We identified a higher amplitude P300 in response to fast, Aβ‐targeted, versus slow CT‐targeted, stroking touch. In contrast, we identified a previously described, C‐fibre specific, ultra‐late potential (ULP) associated with CT‐targeted input. Of special note as regards the function of CTs is that the amplitude of the ULP was negatively correlated with self‐reported levels of autistic traits, which is consistent with the hypothesized affective and social significance of this response. Taken together, these findings provide further support for distinct discriminative and affective touch systems and suggests the temporal resolution of EEG provides an as yet underutilized tool for exploring individual differences in response sensitivity to CT‐targeted touch.