Biology subjects

Raffone, A.

Publications and source records attributed to Raffone, A..

5 recordsLinked to original sources

bioRxiv2025

Neuroplasticity of directed connectivity in long-term meditation: Evidence from EEG Granger causality

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.

neuroscience↗

bioRxiv2025

Distinct patterns of directed brain connectivity in focused attention, open monitoring and loving kindness meditation: An EEG Granger causality study with long-term meditators

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.

neuroscience↗

bioRxiv2025

Differential Effects of Meditation States and Traits on the Neural Mechanisms of Pain Processing

ObjectivesThe main objective of the present study was to explore the effects of different types of meditation on the neurophysiologic mechanisms of pain processing. MethodsEEG 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. ResultsSTM 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. ConclusionsDifferent 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.

neuroscience↗

bioRxiv2025

Meditation induces shifts in neural oscillations, braincomplexity and critical dynamics: Novel insights fromMEG

While the beneficial impacts of meditation are increasingly acknowledged, its underlying neural mechanisms remain poorly understood. We examined the electrophysiological brain signals of expert Buddhist monks during two established meditation methods known as Samatha and Vipassana, which employ focused attention and open monitoring technique. By combining source-space magnetoencephalography (MEG) with advanced signal processing and machine learning tools, we provide an unprecedented assessment of the role of brain oscillations, complexity and criticality in meditation. In addition to power spectral density (PSD), we computed long-range temporal correlations (LRTC), deviation from criticality coefficient (DCC), Lempel-Ziv complexity (LZC), 1/f slope, Higuchi fractal dimension (HFD), and spectral entropy. Our findings indicate increased levels of neural signal complexity during both meditation practices compared to the resting state, along-side widespread reductions in gamma-band LRTC and 1/f slope. Importantly, the DCC analysis revealed a separation between Samatha and Vipassana, suggesting that their distinct phenomenological properties are mediated by specific computational characteristics of their dynamic states. Furthermore, in contrast to most previous reports, we observed a decrease in oscillatory gamma power during meditation, a divergence we attribute to the correction of the power spectrum by the 1/f slope. We discuss how these results advance our comprehension of the neural processes associated with focused attention and open monitoring meditation practices.

neuroscience↗

bioRxiv2019

Disentangling functional connectivity effects of age and expertise in long-term meditators

The effects of intensive meditation practices on the functional and structural organization of the human brain have been addressed by a growing number of neuroscientific studies. However, the different modulations of meditation expertise and of ageing, in the underlying brain areas and networks, have not yet been fully elucidated. These effects should be distinguished in order to clarify how long-term meditation can modulate the connectivity between brain areas. To address this issue, we tested whether meditation expertise and age can be predicted from the multivariate pattern of functional Magnetic Resonance Imaging connectivity, in Theravada Buddhist monks with long-term practice in two different meditation forms: Focused Attention (FA) and Open Monitoring (OM). We found that functional connectivity patterns in both meditation forms can be used to predict expertise and age of long-term meditators. Our findings suggest that meditation expertise is associated with meditation-specific brain networks modulations, while age-related modifications are general and independent from the meditation type. Specifically, expertise modulated patterns during FA meditation include nodes and connections implicated in focusing, sustaining and monitoring attention, while the predictive patterns during OM meditation include nodes associated with cognitive and affective monitoring. Thus, the two forms of meditation may differentially contribute to counteract the effects of neurocognitive decline with ageing by neuroplasticity of brain networks.

neuroscience↗