Mechanisms of white matter change induced by meditation training

Determining the feasibility and acceptability of a randomized telehealth pilot study for veterans with chronic multisymptom illness

BACKGROUND

The shift toward a patient-centered and whole health care model offers a promising approach for the management of symptoms among veterans with chronic multisymptom illness (CMI). A behavioral intervention aimed at reducing cognitive control dysregulation which is a component of impairments common among veterans with CMI may be helpful. Therefore, a pilot study was conducted to explore the feasibility, safety, and acceptability of a telehealth mental and physical (MAP) training intervention among veterans with CMI.

METHODS

Utilizing a two-arm randomized trial, participants were either randomized to 8 weeks of a directed MAP training protocol (dMAP) that received weekly guidance via text messaging or 8 weeks of self-guided MAP training (sgMAP) which did not receive guidance aside from the intervention goals. The MAP intervention was the same for both groups except for the delivery and consisted of two MAP training sessions and one telephone health coaching session per week. The primary aim of the study was to evaluate the feasibility (e.g., recruitment, retention, and adherence rates; amount of missing data), safety (e.g., adverse events), and acceptability (e.g., satisfaction) of a telehealth MAP intervention.

RESULTS

Out of 44 potentially eligible veterans, 26 were randomized to either the dMAP group (n = 13) or the sgMAP group (n = 13), resulting in a recruitment rate of 59% (26/44 patients). Two participants withdrew after randomization, resulting in 24 participants used for analyses. The retention rates at endpoint and 3-month follow-up were 79.2% (19/24; dMAP:sgMAP = 9:10) and 62.5% (15/24; dMAP:sgMAP = 7:8), respectively. Participants completed an average of 48.2% of the MAP sessions (7.7/16 sessions; dMAP:sgMAP = 7.9:7.5 sessions) and 82.8% of the health coaching sessions (6.6/8 sessions; dMAP:sgMAP = 7.2:6.2 sessions). Missing data was minimal, and no adverse events related to the study were reported. Acceptability was high as veterans were satisfied with the wearables and valued the health coaching support.

CONCLUSIONS

This pilot study provides insights into the feasibility of a large-scale randomized control trial that promotes meditation and physical activity to augment cognitive control to facilitate self-regulation. Future efforts should expand recruitment strategies and add internal data quality monitoring.

TRIAL REGISTRATION

NCT04164667, retrospectively registered November 12, 2019, https://clinicaltrials.gov/study/NCT04164667.

Loving-Kindness Meditation: Systematic Review of Neuroimaging Correlates in Long-Term Practitioners and Clinical Implications

INTRODUCTION

Loving-kindness meditation (LKM), a meditation type focused on nurturing love and compassion for oneself and others, has been shown to provide mental health benefits, and LKM interventions are being investigated for mental disorders. The benefits of long-term practice, such as increased self-compassion, greater cognitive and affective empathy, and prosocial behavior, are proposed to be due to neuroplastic changes that support well-being. This systematic review aims to summarize the differences in brain structure and function in long-term practitioners (LTPs) of LKM versus controls to identify possible underlying mechanisms that support mental health and drive treatment effect.

METHODS

The literature search included Google Scholar, PubMed, and APA PsycINFO from inception through November 13, 2023.

RESULTS

After review, five studies (64 LTPs and 67 controls total) were included. Brain regions with between-group differences reported in at least two studies include the superior parietal lobe, inferior frontal gyrus, medial frontal lobe, and insular cortex.

CONCLUSION

These areas are responsible for self-compassion, cognitive and affective empathy, and prosociality-personal qualities believed to be fostered through LKM practice. Longitudinal neuroimaging and neurophysiological studies incorporating LKM interventions for specific mental disorders are needed to further inform the biological basis of these treatments and may provide surrogate outcome measures for future clinical trials to refine this promising treatment modality.

From Infancy to Childhood: A Comprehensive Review of Event- and Task-Related Brain Oscillations

Brain development from infancy through childhood involves complex structural and functional changes influenced by both internal and external factors. This review provides a comprehensive analysis of event and task-related brain oscillations, focusing on developmental changes across different frequency bands, including delta, theta, alpha, beta, and gamma. Electroencephalography (EEG) studies highlight that these oscillations serve as functional building blocks for sensory and cognitive processes, with significant variations observed across different developmental stages. Delta oscillations, primarily associated with deep sleep and early cognitive demands, gradually diminish as children age. Theta rhythms, crucial for attention and memory, display a distinct pattern in early childhood, evolving with cognitive maturation. Alpha oscillations, reflecting thalamocortical interactions and cognitive performance, increase in complexity with age. Beta rhythms, linked to active thinking and problem-solving, show developmental differences in motor and cognitive tasks. Gamma oscillations, associated with higher cognitive functions, exhibit notable changes in response to sensory stimuli and cognitive tasks. This review underscores the importance of understanding oscillatory dynamics to elucidate brain development and its implications for sensory and cognitive processing in childhood. The findings provide a foundation for future research on developmental neuroscience and potential clinical applications.

Enhanced amygdala-anterior cingulate white matter structural connectivity in Sahaja Yoga Meditators

OBJECTIVE

To study the white matter connections between anterior cingulate cortex, anterior insula and amygdala as key regions of the frontal-limbic network that have been related to meditation.

DESIGN

Twenty experienced practitioners of Sahaja Yoga Meditation and twenty nonmeditators matched on age, gender and education level, were scanned using Diffusion Weighted Imaging, using a 3T scanner, and their white matter connectivity was compared using diffusion tensor imaging analyses.

RESULTS

There were five white matter fiber paths in which meditators showed a larger number of tracts, two of them connecting the same area in both hemispheres: the left and right amygdalae and the left and right anterior insula; and the other three connecting left anterior cingulate with the right anterior insula, the right amygdala and the left amygdala. On the other hand, non-meditators showed larger number of tracts in two paths connecting the left anterior insula with the left amygdala, and the left anterior insula with the left anterior cingulate.

CONCLUSIONS

The study shows that long-term practice of Sahaja Yoga Meditation is associated with larger white matter tracts strengthening interhemispheric connections between limbic regions and connections between cingulo-amygdalar and cingulo-insular brain regions related to top-down attentional and emotional processes as well as between top-down control functions that could potentially be related to the witness state perceived through the state of mental silence promoted with this meditation. On the other hand, reduced connectivity strength in left anterior insula in the meditation group could be associated to reduced emotional processing affecting top-down processes.

Bilateral anterior corona radiata microstructure organisation relates to impaired social cognition in schizophrenia

OBJECTIVE

The Corona Radiata (CR) is a large white matter tract in the brain comprising of the anterior CR (aCR), superior CR (sCR), and posterior CR (pCR), which have associations with cognition, self-regulation, and, in schizophrenia, positive symptom severity. This study tested the hypothesis that the microstructural organisation of the aCR, as measured by Fractional Anisotropy (FA) using Diffusion Tensor Imaging (DTI), would relate to poorer social cognitive outcomes and higher positive symptom severity for people with schizophrenia, when compared to healthy participants. We further hypothesised that increased positive symptoms would relate to poorer social cognitive outcomes.

METHODS

Data were derived from n = 178 healthy participants (41 % females; 36.11 ± 12.36 years) and 58 people with schizophrenia (30 % females; 42.4 ± 11.1 years). The Positive and Negative Symptom Severity Scale measured clinical symptom severity. Social Cognition was measured using the Reading the Mind in the Eyes Test (RMET) Total Score, as well as the Positive, Neutral, and Negative stimuli valence. The ENIGMA-DTI protocol tract-based spatial statistics (TBSS) was used.

RESULTS

There was a significant difference in FA for the CR, in individuals with schizophrenia compared to healthy participants. On stratification, both the aCR and pCR were significantly different between groups, with patients showing reduced white matter tract microstructural organisation. Significant negative correlations were observed between positive symptomatology and reduced microstructural organisation of the aCR. Performance for RMET negative valence items was significantly correlated bilaterally with the aCR, but not the sCR or pCR, and no relationship to positive symptoms was observed.

CONCLUSIONS

These data highlight specific and significant microstructural white-matter differences for people with schizophrenia, which relates to positive clinical symptomology and poorer performance on social cognition stimuli. While reduced FA is associated with higher positive symptomatology in schizophrenia, this study shows the specific associated with anterior frontal white matter tracts and reduced social cognitive performance. The aCR may have a specific role to play in frontal-disconnection syndromes, psychosis, and social cognitive profile within schizophrenia, though further research requires more sensitive, specific, and detailed consideration of social cognition outcomes.

The Utility of Meditation and Mindfulness-Based Interventions in the Time of COVID-19: A Theoretical Proposition and Systematic Review of the Relevant Prison, Quarantine and Lockdown Literature

As of July 20, 2021, Covid-19 has killed 4,086,000 people, infected at least 190,169,833 others, and devastated the world's economy. To slow the spread of the virus, numerous governments instituted "lockdown" policies and quarantines, limiting social interactions to the immediate household. The experience of isolation and uncertainty have contributed to increased fear, anxiety, and loneliness; with limited options of research-supported interventions. Although different in nature, the experiences of quarantine and lockdown have been likened to incarceration. Past research has found meditation and mindfulness-based interventions (MBIs) to be effective psychological treatments for prisoners and may therefore translate well into effective methods for the maintenance of psychological well-being for individuals quarantined during the pandemic. More recently, research investigating the effects of meditation and MBIs during the pandemic have demonstrated preliminary evidence for beneficial psychological improvements. In accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA), the current narrative review paper: 1) examines the parallels and differences between the experience of quarantine and imprisonment, 2) investigates the mechanisms through which meditation and mindfulness enact their effects, and 3) systematically reviews literature on the benefits of various types of meditation and MBIs for inmates and individuals in lockdown or quarantine. With this knowledge, the public can garner applicable insight into the potential use of meditation and MBIs for individuals forced to cope with pandemic lockdowns and quarantines. Two hundred and twenty one (221) articles were identified through Pubmed and Google Scholar, and 24 articles were ultimately included in the manuscript.

Mindfulness-Enhanced Computerized Cognitive Training for Depression: An Integrative Review and Proposed Model Targeting the Cognitive Control and Default-Mode Networks

Depression is often associated with co-occurring neurocognitive deficits in executive function (EF), processing speed (PS) and emotion regulation (ER), which impact treatment response. Cognitive training targeting these capacities results in improved cognitive function and mood, demonstrating the relationship between cognition and affect, and shedding light on novel targets for cognitive-focused interventions. Computerized cognitive training (CCT) is one such new intervention, with evidence suggesting it may be effective as an adjunct treatment for depression. Parallel research suggests that mindfulness training improves depression via enhanced ER and augmentation of self-referential processes. CCT and mindfulness training both act on anti-correlated neural networks involved in EF and ER that are often dysregulated in depression—the cognitive control network (CCN) and default-mode network (DMN). After practicing CCT or mindfulness, downregulation of DMN activity and upregulation of CCN activity have been observed, associated with improvements in depression and cognition. As CCT is posited to improve depression via enhanced cognitive function and mindfulness via enhanced ER ability, the combination of both forms of training into mindfulness-enhanced CCT (MCCT) may act to improve depression more rapidly. MCCT is a biologically plausible adjunct intervention and theoretical model with the potential to further elucidate and target the causal mechanisms implicated in depressive symptomatology. As the combination of CCT and mindfulness has not yet been fully explored, this is an intriguing new frontier. The aims of this integrative review article are four-fold: (1) to briefly review the current evidence supporting the efficacy of CCT and mindfulness in improving depression; (2) to discuss the interrelated neural networks involved in depression, CCT and mindfulness; (3) to present a theoretical model demonstrating how MCCT may act to target these neural mechanisms; (4) to propose and discuss future directions for MCCT research for depression.

Meditation-induced effects on whole-brain structural and effective connectivity

In the past decades, there has been a growing scientific interest in characterizing neural correlates of meditation training. Nonetheless, the mechanisms underlying meditation remain elusive. In the present work, we investigated meditation-related changes in functional dynamics and structural connectivity (SC). For this purpose, we scanned experienced meditators and control (naive) subjects using magnetic resonance imaging (MRI) to acquire structural and functional data during two conditions, resting-state and meditation (focused attention on breathing). In this way, we aimed to characterize and distinguish both short-term and long-term modifications in the brain’s structure and function. First, to analyze the fMRI data, we calculated whole-brain effective connectivity (EC) estimates, relying on a dynamical network model to replicate BOLD signals’ spatio-temporal structure, akin to functional connectivity (FC) with lagged correlations. We compared the estimated EC, FC, and SC links as features to train classifiers to predict behavioral conditions and group identity. Then, we performed a network-based analysis of anatomical connectivity. We demonstrated through a machine-learning approach that EC features were more informative than FC and SC solely. We showed that the most informative EC links that discriminated between meditators and controls involved several large-scale networks mainly within the left hemisphere. Moreover, we found that differences in the functional domain were reflected to a smaller extent in changes at the anatomical level as well. The network-based analysis of anatomical pathways revealed strengthened connectivity for meditators compared to controls between four areas in the left hemisphere belonging to the somatomotor, dorsal attention, subcortical and visual networks. Overall, the results of our whole-brain model-based approach revealed a mechanism underlying meditation by providing causal relationships at the structure-function level.

Mining the Mind: Linear Discriminant Analysis of MEG Source Reconstruction Time Series Supports Dynamic Changes in Deep Brain Regions During Meditation Sessions

Meditation practices have been claimed to have a positive effect on the regulation of mood and emotions for quite some time by practitioners, and in recent times there has been a sustained effort to provide a more precise description of the influence of meditation on the human brain. Longitudinal studies have reported morphological changes in cortical thickness and volume in selected brain regions due to meditation practice, which is interpreted as an evidence its effectiveness beyond the subjective self reporting. Using magnetoencephalography (MEG) or electroencephalography to quantify the changes in brain activity during meditation practice represents a challenge, as no clear hypothesis about the spatial or temporal pattern of such changes is available to date. In this article we consider MEG data collected during meditation sessions of experienced Buddhist monks practicing focused attention (Samatha) and open monitoring (Vipassana) meditation, contrasted by resting state with eyes closed. The MEG data are first mapped to time series of brain activity averaged over brain regions corresponding to a standard Destrieux brain atlas. Next, by bootstrapping and spectral analysis, the data are mapped to matrices representing random samples of power spectral densities in [Formula: see text], [Formula: see text], [Formula: see text], and [Formula: see text] frequency bands. We use linear discriminant analysis to demonstrate that the samples corresponding to different meditative or resting states contain enough fingerprints of the brain state to allow a separation between different states, and we identify the brain regions that appear to contribute to the separation. Our findings suggest that the cingulate cortex, insular cortex and some of the internal structures, most notably the accumbens, the caudate and the putamen nuclei, the thalamus and the amygdalae stand out as separating regions, which seems to correlate well with earlier findings based on longitudinal studies.

Increasing the amplitude of intrinsic theta in the human brain

In a mouse study we found increased myelination of pathways surrounding the anterior cingulate cortex (ACC) following stimulation near the theta rhythm (4-8 Hz), and evidence that this change in connectivity reduced behavioral anxiety. We cannot use the optogenetic methods with humans that were used in our mouse studies. This paper examines whether it is possible to enhance intrinsic theta amplitudes in humans using less invasive methods. The first experiment compares electrical, auditory and biofeedback as methods for increasing intrinsic theta rhythm amplitudes in the Anterior Cingulate Cortex (ACC). These methods are used alone or in conjunction with a task designed to activate the same area. The results favor using electrical stimulation in conjunction with a task targeting this region. Stimulating the ACC increases intrinsic theta more in this area than in a control area distant from the site of stimulation, suggesting some degree of localization of the stimulation. In Experiment 2, we employed electrical stimulation with the electrodes common to each person, or with electrodes selected from an individual head model. We targeted the ACC or Motor Cortex (PMC). At baseline, intrinsic theta is higher in the ACC than the PMC. In both areas, theta can be increased in amplitude by electrical stimulation plus task. In the PMC, theta levels during stimulation plus task are not significantly higher than during task alone. There is no significant difference between generic and individual electrodes. We discuss steps needed to determine whether we can use the electrical stimulation + task to improve the connectivity of white matter in different brain areas.

Anterior Cingulate Cortex in Addiction: New Insights for Neuromodulation

OBJECTIVES

Substance use disorder (SUD) is characterized by compulsive use of addictive substances with considerable impact on both the medical system and society as a whole. The craving of substances leads to relapse in the majority of patients within one year of traditional treatments. In recent decades, neuromodulation approaches have emerged as potential novel treatments of SUD, but the ideal neural target remains contentious.

MATERIALS AND METHODS

In this review, we discuss new insights on the anterior cingulate cortex (ACC) as a neuromodulation target for SUD.

RESULTS AND CONCLUSION

First, we illustrate that the ACC serves as a central "hub" in addiction-related neural networks of cognitive functions, including, but not limited to, decision-making, cognitive inhibition, emotion, and motivation. Then, we summarize the literature targeting the ACC to treat SUDs via available neuromodulation approaches. Finally, we propose potential directions to improve the effect of stimulating the ACC in SUD treatment. We emphasize that the ACC can be divided into at least four sub-regions, which have distinctive functions and connections. Studies focusing on these sub-regions may help to develop more precise and effective ACC stimulation according to patients' symptom profiles and cognitive deficits.

Cortical reorganization processes in meditation naïve participants induced by 7 weeks focused attention meditation training

BACKGROUND

Based on the evidence that meditation is associated with numerous beneficial effects on well-being and reduced stress-related symptoms, mindfulness-based techniques were increasingly implemented into psychotherapeutic programs. However, different meditation styles and the cross-sectional nature of most previous analyses resulted in a great variety of morphometric findings. The present study aims to elucidate cortical reorganization processes and altered axonal integrity caused by short-term meditation training, and benefits from solely using focused attention meditation (FAM).

METHODS

3 T MRI, including T1-MPRAGE and diffusion-weighted sequences, was performed in 27 healthy, meditation naïve participants (age: 43 ± 12.4 years) pre and post FAM meditation training (duration: 7.3 ± 0.4 weeks). Voxel-based morphometry was applied to assess brain changes in gray and white matter. Questionnaires were filled out by the individuals at both time-points to evaluate quality of life and self-awareness deficits.

RESULTS

The major findings comprised (i) gray matter increases in the insula, the caudate nucleus and frontal cortices, (ii) decreases in extended parietotemporal regions, the right medial prefrontal cortex and the parahippocampal gyrus, as well as (iii) fractional anisotropy increases of the right hippocampus, the basal ganglia and adjacent regions. Regression analysis revealed an association of specific alterations with reduced levels of state anxiety.

CONCLUSIONS

FAM training induced a broad range of dynamic brain alterations even within few weeks of training. Interestingly, this cohort revealed more, and partially different patterns of structural gray matter change compared to prior studies. The broad impact on neuronal organization processes may reflect more general outcomes related to health and well-being.

From Evaluation to Prediction: Behavioral Effects and Biological Markers of Cognitive Control Intervention

Although the intervention effectiveness of cognitive control is disputed, some methods, such as single-task training, integrated training, meditation, aerobic exercise, and transcranial stimulation, have been reported to improve cognitive control. This review of recent advances from evaluation to prediction of cognitive control interventions suggests that brain modularity may be an important candidate marker for informing clinical decisions regarding suitable interventions. The intervention effect of cognitive control has been evaluated by behavioral performance, transfer effect, brain structure and function, and brain networks. Brain modularity can predict the benefits of cognitive control interventions based on individual differences and is independent of intervention method, group, age, initial cognitive ability, and education level. The prediction of cognitive control intervention based on brain modularity should extend to task states, combine function and structure networks, and assign different weights to subnetwork modularity.

Possible Effect of Binaural Beat Combined With Autonomous Sensory Meridian Response for Inducing Sleep

Sleep is important to maintain physical and cognitive functions in everyday life. However, the prevalence of sleep disorders is on the rise. One existing solution to this problem is to induce sleep using an auditory stimulus. When we listen to acoustic beats of two tones in each ear simultaneously, a binaural beat is generated which induces brain signals at a specific desired frequency. However, this auditory stimulus is uncomfortable for users to listen to induce sleep. To overcome this difficulty, we can exploit the feelings of calmness and relaxation that are induced by the perceptual phenomenon of autonomous sensory meridian response (ASMR). In this study, we proposed a novel auditory stimulus for inducing sleep. Specifically, we used a 6 Hz binaural beat corresponding to the center of the theta band (4-8 Hz), which is the frequency at which brain activity is entrained during non-rapid eye movement (NREM) in sleep stage 1. In addition, the "ASMR triggers" that cause ASMR were presented from natural sound as the sensory stimuli. In session 1, we combined two auditory stimuli (the 6 Hz binaural beat and ASMR triggers) at three-decibel ratios to find the optimal combination ratio. As a result, we determined that the combination of a 30:60 dB ratio of binaural beat to ASMR trigger is most effective for inducing theta power and psychological stability. In session 2, the effects of these combined stimuli (CS) were compared with an only binaural beat, only the ASMR trigger, or a sham condition. The combination stimulus retained the advantages of the binaural beat and resolved its shortcomings with the ASMR triggers, including psychological self-reports. Our findings indicate that the proposed auditory stimulus could induce the brain signals required for sleep, while simultaneously keeping the user in a psychologically comfortable state. This technology provides an important opportunity to develop a novel method for increasing the quality of sleep.

Frontal theta activity and white matter plasticity following mindfulness meditation

Both brain alpha and theta power have been examined in the mindfulness meditation literature and suggested as key biological signatures that potentially facilitate a successful meditative state. However, the exact role of how alpha and theta waves contribute to the initiation and maintenance of a meditative state remains elusive. In this perspective paper, we discuss the role of frontal midline theta (FMθ) activity in brain white matter plasticity following mindfulness meditation. In accordance with the previous studies in humans, we propose that FMθ activity indexes the control needed to maintain the meditation state; whereas alpha activity is related to the preparation needed to achieve the meditative state. Without enough mental preparation, one often struggles with and has difficulty achieving a meditative state. Animal work provides further evidence supporting the hypothesis that mindfulness meditation induces white matter changes through increasing FMθ activity. These studies shed light on how to effectively enhance brain plasticity through mindfulness meditation.

Illuminating the Neural Circuits Underlying Orienting of Attention

Human neuroimaging has revealed brain networks involving frontal and parietal cortical areas as well as subcortical areas, including the superior colliculus and pulvinar, which are involved in orienting to sensory stimuli. Because accumulating evidence points to similarities between both overt and covert orienting in humans and other animals, we propose that it is now feasible, using animal models, to move beyond these large-scale networks to address the local networks and cell types that mediate orienting of attention. In this opinion piece, we discuss optogenetic and related methods for testing the pathways involved, and obstacles to carrying out such tests in rodent and monkey populations.

Temperament and brain networks of attention

The attention networks of the human brain are important control systems that develop from infancy into adulthood. While they are common to everyone, they differ in efficiency, forming the basis of individual differences in attention. We have developed methods for measuring the efficiency of these networks in older children and adults and have also examined their development from infancy. During infancy the alerting and orienting networks are dominant in control of the infant's actions, but later an executive network dominates. Each network has been associated with its main neuromodulator and these have led to associations with genes related to that network neuromodulator. The links between parent reports of their child's effortful control and the executive attention network allow us to associate molecular mechanisms to fundamental behavioural outcomes.This article is part of the theme issue 'Diverse perspectives on diversity: multi-disciplinary approaches to taxonomies of individual differences'.

Rehabilitating the brain through meditation and electrical stimulation

This paper is a review of our recent studies and ideas related to the neuropsychological issues that Robert Rafal and I worked together to understand attention and hopefully improve it in a variety of patients. Rehabilitation is also a goal of my current research to determine if non invasive stimuli can improve white matter in humans. We have found that fractional anisotropy (FA) is improved in pathways surrounding the anterior cingulate cortex (ACC) following two week to four weeks of meditation training. We hypothesized that the frontal theta increased following meditation training might be a cause of the improved connectivity. This was confirmed by a mouse study using optogenetics to impose theta rhythms in the ACC. We have evidence that electrical stimulation while performing a task that activates the ACC can also increase theta. We plan studies to determine whether two to four weeks of stimulation can improve FA in pathways surrounding the anterior cingulate.

Changes in white matter in mice resulting from low-frequency brain stimulation

Recent reports have begun to elucidate mechanisms by which learning and experience produce white matter changes in the brain. We previously reported changes in white matter surrounding the anterior cingulate cortex in humans after 2-4 weeks of meditation training. We further found that low-frequency optogenetic stimulation of the anterior cingulate in mice increased time spent in the light in a light/dark box paradigm, suggesting decreased anxiety similar to what is observed following meditation training. Here, we investigated the impact of this stimulation at the cellular level. We found that laser stimulation in the range of 1-8 Hz results in changes to subcortical white matter projection fibers in the corpus callosum. Specifically, stimulation resulted in increased oligodendrocyte proliferation, accompanied by a decrease in the g-ratio within the corpus callosum underlying the anterior cingulate cortex. These results suggest that low-frequency stimulation can result in activity-dependent remodeling of myelin, giving rise to enhanced connectivity and altered behavior.

A critical view of the quest for brain structural markers of Albert Einstein's special talents (a pot of gold under the rainbow)

Assertions regarding attempts to link glial and macrostructural brain events with cognitive performance regarding Albert Einstein, are critically reviewed. One basic problem arises from attempting to draw causal relationships regarding complex, delicately interactive functional processes involving finely tuned molecular and connectivity phenomena expressed in cognitive performance, based on highly variable brain structural events of a single, aged, formalin fixed brain. Data weaknesses and logical flaws are considered. In other instances, similar neuroanatomical observations received different interpretations and conclusions, as those drawn, e.g., from schizophrenic brains. Observations on white matter events also raise methodological queries. Additionally, neurocognitive considerations on other intellectual aptitudes of A. Einstein were simply ignored.

Enhanced White Matter Integrity in Corpus Callosum of Long-Term Brahmakumaris Rajayoga Meditators

Meditation has a versatile nature to affect cognitive functioning of human brain. Recent researches demonstrated its effects on white matter (WM) properties of human brain. In this research, we aim to investigate WM microstructure of corpus callosum (CC) in long-term meditators (LTMs) of rajayoga meditation using diffusion tensor imaging. For this cross-sectional analysis, 22 LTMs and 17 control participants of age ranging from 30 to 50 years were recruited. Results show high fractional anisotropy values with low mean diffusivity in whole as well as different segments of CC in the LTM group. Also the experience of meditation was correlated with WM properties of CC tracts. Findings may suggest rajayoga meditation to bring potential changes in microstructure of CC segments. Further studies are suggested in clinical population to check its validity and efficacy against disorders involving agenesis of WM.

All Wrapped Up: Environmental Effects on Myelination

To date, studies have demonstrated the dynamic influence of exogenous environmental stimuli on multiple regions of the brain. This environmental influence positively and negatively impacts programs governing myelination, and acts on myelinating oligodendrocyte (OL) cells across the human lifespan. Developmentally, environmental manipulation of OL progenitor cells (OPCs) has profound effects on the establishment of functional cognitive, sensory, and motor programs. Furthermore, central nervous system (CNS) myelin remains an adaptive entity in adulthood, sensitive to environmentally induced structural changes. Here, we discuss the role of environmental stimuli on mechanisms governing programs of CNS myelination under normal and pathological conditions. Importantly, we highlight how these extrinsic cues can influence the intrinsic power of myelin plasticity to promote functional recovery.

Methylation polymorphism influences practice effects in children during attention tasks

Epigenetic mechanisms mediate the influence of experience on gene expression. Methylation is a principal method for inducing epigenetic effects on DNA. In this paper, we examine alleles of the methylenetetrahydrofolate reductase (MTHFR) gene that vary enzyme activity, altering the availability of the methyl donor and thus changing the efficiency of methylation. We hypothesized that alleles of the MTHFR gene would influence behavior in an attention-related task in conjunction with genes known to influence attention. We found that seven-year-old children homozygous for the C allele of MTHFR in interaction with the catechol O-methyltransferase (COMT) gene showed greater improvement in overall reaction time (RT) and in conflict resolution with practice on the Attention Network Test (ANT). This finding indicates that methylation may operate on or through genes that influence executive network operation. However, MTHFR T allele carriers showed faster overall RT and conflict resolution. Some children showed an initial improvement in ANT RT followed by a decline in performance, and we found that alleles of the dopamine beta-hydroxylase (DBH) gene were related to this performance decline. These results suggest a genetic dissociation between improvement while learning a skill and reduction in performance with continued practice.

Rhythmic brain stimulation reduces anxiety-related behavior in a mouse model based on meditation training

Meditation training induces changes at both the behavioral and neural levels. A month of meditation training can reduce self-reported anxiety and other dimensions of negative affect. It also can change white matter as measured by diffusion tensor imaging and increase resting-state midline frontal theta activity. The current study tests the hypothesis that imposing rhythms in the mouse anterior cingulate cortex (ACC), by using optogenetics to induce oscillations in activity, can produce behavioral changes. Mice were randomly assigned to groups and were given twenty 30-min sessions of light pulses delivered at 1, 8, or 40 Hz over 4 wk or were assigned to a no-laser control condition. Before and after the month all mice were administered a battery of behavioral tests. In the light/dark box, mice receiving cortical stimulation had more light-side entries, spent more time in the light, and made more vertical rears than mice receiving rhythmic cortical suppression or no manipulation. These effects on light/dark box exploratory behaviors are associated with reduced anxiety and were most pronounced following stimulation at 1 and 8 Hz. No effects were seen related to basic motor behavior or exploration during tests of novel object and location recognition. These data support a relationship between lower-frequency oscillations in the mouse ACC and the expression of anxiety-related behaviors, potentially analogous to effects seen with human practitioners of some forms of meditation.

Promises and pitfalls of relating alteration of white matter pathways causing improvement in cognitive performance

Here, we argue systematically about the promises and pitfalls of relating Human Connectome to cognitive enhancement. We also highlight three key areas where further resolution is required before the generalization of the white-matter-related cause of cognitive enhancement across a variety of cognitive modalities is made. These key areas are: (a) inherent limitations in estimating of diffusion-weighted anisotropy index near volumes with high abundance of crossing fibers; (b) species differences in cell types and only a putative link between brain rhythms and modulation of activity in precursor cells in rodents;

Circuitry of self-control and its role in reducing addiction

We discuss the idea that addictions can be treated by changing the mechanisms involved in self-control with or without regard to intention. The core clinical symptoms of addiction include an enhanced incentive for drug taking (craving), impaired self-control (impulsivity and compulsivity), negative mood, and increased stress re-activity. Symptoms related to impaired self-control involve reduced activity in control networks including anterior cingulate (ACC), adjacent prefrontal cortex (mPFC), and striatum. Behavioral training such as mindfulness meditation can increase the function of control networks and may be a promising approach for the treatment of addiction, even among those without intention to quit.

How changes in white matter might underlie improved reaction time due to practice

Why does training on a task reduce the reaction time for performing it? New research points to changes in white matter pathways as one likely mechanism. These pathways connect remote brain areas involved in performing the task. Genetic variations may be involved in individual differences in the extent of this improvement. If white matter change is involved in improved reaction time with training, it may point the way toward understanding where and how generalization occurs. We examine the hypothesis that brain pathways shared by different tasks may result in improved performance of cognitive tasks remote from the training.