Who you really are; the default mode network

The default mode network has a crucial but poorly understood role in how meditation influences brain structure and function. This paper sets out some of the current thinking regarding self-generated thought.

Meditation and the defaulyt mode network.
What is your brain doing when you are day dreaming?

Authors: Andrews‐Hanna, J. R., Smallwood, J., & Spreng, R. N.

Year: 2014

Title: The default network and self‐generated thought: component processes, dynamic control, and clinical relevance

Summary: It is frequently suggested that neuroscience is still in its infancy, this becomes patently clear when you start to consider how little we know about the default mode network (DMN). The DMN, also known as the default network (DN) or the task-negative network (TNN) is most active when humans are in a resting state. In short, the DMN is the network that takes over when we are not actively engaged in a specific task. Surprisingly it was assumed that the brain was resting when not engaged in an externally focussed activity. This assumption was surprising because scientists know that their brains are capable of complex processes such as mind wandering when they are not reacting to the external environment. However, only when it was demonstrated that functional brain activity could reach similar levels in task and non-task modes did the investigation into the DMN begin in earnest. This has particular relevance for meditators and contemplative science, as the DMN is often the direct and indirect target for meditation methods.

Andrews‐Hanna,  Smallwood and Spreng produced a review of the leading findings linked to the DMN, which they describe as an anatomically diffuse global network.  Their primary focus is the DMN and self-generated thought, thought that arise without external sensory stimulus. Describing much of the recent research in the field they conclude that the DMN plays an integrated role in a wide range of neurological functions. Thus both normal and abnormal mental health is dependent on activity and functional connectivity within the DMN and links to other neural networks. The paper provides a useful background to contemplative scientists looking for an understanding of how meditation might influence human behaviour.

Link:  www.ncbi.nlm.nih.gov

Brain health in middle age; the science of meditation and mindfulness

Meditation and mindfulness may help to keep your brain young

man sitting on chair beside table

 

Authors: Fotuhi, M., Lubinski, B., Trullinger, M., Hausterman, N., Riloff, T., Hadadi, M., & Raji, C. A.

Year: 2016

Title: A personalized 12‐week ” Brain Fitness Program” for improving cognitive function and increasing the volume of hippocampus in elderly with mild cognitive impairment.

Summary: The idea that brain function inevitably declines as people grow older is firmly established in both clinical and cognitive branches of psychology. This particular study is one of only a handful that I have seen to suggest, that even in retirement, people can maintain and even increase both structure and function in the brain. Participants of retirement age with a diagnosis of mild cognitive impairment (MCI) were asked to engage in a number of activities linked to brain health. They included: cognitive stimulation, Omega 3 supplements, some physical exercise, a change in diet and mindfulness meditation. Participant undertook a range of cognitive tests before the interventions and at the end of the experiment.

Results showed that 84% of participants saw an improvement in their cognitive performance. Further neuroimaging examinations revealed that a majority of a sample of the participants also demonstrated no decline or an actual increase in the volume of the hippocampus. Although this was a preliminary study with a number of methodological problems, it is suggestive that people may have a lot more control over brain structure and function than is generally assumed. This kind of ‘shotgun’ approach can support general theories but adds little to our understanding of the extent to which particular interventions (or combination of interventions) may offer benefit. It also makes the establishment of robust scientific theory a challenge, as no single theory can incorporate such a wide range of activities. For example with a new diet, can cognitive changes be attributed to the food that was no longer being eaten or the new food? Or a combination of the two? However simply to demonstrate that older adults can experience increased structure in certain brain regions is an important contribution to our understanding of the human brain.

Link: https://neurogrow.com

Intelligence linked to brain size

Not a surprising headline until you consider that Dr Erhan Genç and Christoph Fraenz at Ruhr-Universität Bochum are reported as suggesting that people with higher scores on an intelligence test were found to have smaller brain structures. […]

Meditation changes brain size?
Meditation can change brain size, but not only in one direction

Not a surprising headline until you consider that Dr Erhan Genç and Christoph Fraenz at Ruhr-Universität Bochum are reported as suggesting that people with higher scores on an intelligence test were found to have smaller brain structures.

Brains are extremely complex organs and many aspects of their function and structure are not yet fully understood. However, we do know that neurons usually gather data from adjacent (presynaptic) neurons through complex tree-like structures containing many dendrites. The dendrites communicate with their own neuron’s cell body. Based on the messages received through the dendrites, a cell may fire (create an action potential) or not. When an action potential is generated, a message is then sent out to other neurons (postsynaptic) through the axon terminal. The reports of this study (I haven’t read the actual paper yet) is suggestive that people with fewer dendrites feeding into certain neurons in the cerebral cortex had higher IQ scores.

Dendrite (PSF)There are typically large numbers of dendrites communicating with each neuron in the cerebral cortex. There is a putative logic which could argue that smaller dendrite trees could be more efficient. Leading to a greater number of relevant action potentials being created more quickly. Given our limitations in understanding the mechanisms that lead to the generation and maintenance of dendrites, some caution needs to be expressed here. Without an appreciation of what the extra dendrites (in the participants with lower IQ scores) do, and why they are there, the picture is incomplete. Intelligence tests in general and IQ tests, in particular, are regarded by many experts as being reductive. It is possible that people with a history of IQ testing could have developed dendritic structures able to support this activity. But has anything been lost in the process? Are the extra dendrites in the lower IQ scored participants simply inefficient, and of no real benefit?

So what has this got to do with meditation? I wrote recently about structural changes in the brains of meditators. A conclusion from my own investigations was that increases and decreases in brain structures are likely to be the result of intense and sustained meditation practice. So the demonstration that neurological structures become bigger or smaller is probably an unhelpful oversimplification. The relationship between the alteration in structural size in different (interrelated) regions of the brain needs to be understood and then correlated to cognitive functionality if the understanding of the significance of changes is to be approached.

Rather than increasing or decreasing brain structures, meditators should probably think about their practice in terms of its deliverable goals in relation to behaviour. Brain imaging technology is still in its infancy and there are many significant problems still to overcome. We are probably decades away for being certain of the impact of complex human behaviours (like meditation) on brain structure, but we have for centuries been able to relate certain practices with behavioural changes. There are two obvious exceptions to these generalizations, age-related structural decline and changes due to neurodegeneration.

It should reiterate that I haven’t seen the full report of the Genç and Fraenz paper but a report is available at Eureka Alert.

Deepening crisis in meditation research

Is contemporary mindfulness a meditation practice or something different?

pexels-photo-203553.jpeg

Two leading researchers from contemplative science respond to a critical study of meditation and mindfulness research.

Authors: Richard J. Davidson and Cortland J. Dahl

Year: 2018

Title: Outstanding Challenges in Scientific Research on Mindfulness and Meditation

Summary: The article begins by applauding the critique of Van Dam et al. This is only to be expected, published meditation and mindfulness research often falls short of the methodological standards normally required of journal articles in cognitive psychology and neuroscience. The authors address the five points raised by the original paper in a very linear fashion, not appearing to engage with the underlying issues. The same issues that have dogged meditation research since the launch of MBSR. However to summarize the five rebuttals contained in the paper:

1 – The criticisms of meditation research reflect weakness in psychological research more generally.

2 – Contemplative practices are varied and scientific enquiry is only able to understand a few limited forms.

3 – Mindfulness and contemplative practices were not originally therapeutic in nature

4 – Research has failed to understand meditation in a relevant context.

5 – Mobile technology may be able to resolve some of the methodological issues.

Link: http://journals.sagepub.com

Author’s Critique: It is important to note that Davidson and Dahl are leaders in this field, but if they permit I offer some observation as an experienced meditator and trained neuroscientist and cognitive psychologist.

Psychology does not appear to understand meditation in the broadest sense, the (mis)appropriation of the term mindfulness has led contemporary meditation research into a limited field of investigation without clear definitions. For example, the reduction of meditation (or mindfulness) to method alone, existing in isolation to wider cognitive processes is hard to understand in the context of traditional meditation. And it must be acknowledged that the MBSR/MBI movement uses methods ‘congruent’ with traditional meditation.

If we strip the motivation of the meditator from the meditation rationale we change the entire cognitive setting. To use a rough analogy, I can train people to kick a football but if participant A is training just for a course credit and participant B is training to play in the World Cup final we can expect the effect of the training to be different. This doesn’t just mean that comparing traditional and contemporary meditation practices is fraught with difficulty but that the current understanding of how we research meditation needs to be refined. Traditional meditation literature spanning hundreds of years indicates that two people undertaking the same practice may not experience the same effects. Their individual motivation, their capacity to meditate, external conditions such as the availability of a reliable teacher and methods can all play a part. Psychology has the instruments to consider and account for many of the factors presumed to impact on the effect of meditation, but generally, the method alone dominates the thinking of meditation scientists.

Don’t misunderstand me, the study of MBSR and related families of mindfulness are legitimate objects of clinical enquiry and experimental study. They have however unconfirmed connections with mindfulness in its many forms as practised in spiritual traditions. Buddhism is not one unified tradition, there are different approaches to what one might call mindfulness, these extend from ‘bare attention’ through to ‘shine’ as practised in Tibetan traditions. Often shine is only engaged with after many years of stable foundational practice and if approached from the Vajrayana perspective would be embedded in a context of a nondual appreciation of human consciousness.

The ability of the meditation teacher and the degree of challenge to dualistic thinking are just two factors able to meditate the impact of a meditation method. But these and other components are generally ignored by scientific studies, even strategic reviews and meta-studies. In a traditional context, a meditation master may undertake decades of practice and study to understand meditation on theoretical and experiential levels. Therefore the capacity of the meditation teacher is an established factor in the progress of traditional meditation students but this is rarely discussed in the scientific literature. The point is that the assumption that the teaching of the meditation method is not a potential variable in any experiment is probably unscientific. The Van Dam et al. study is one of the first to suggest the role of the teacher can influence the effect of meditation training on participants.

Leaving aside traditional mindfulness methods, the reliability of the term mindfulness in relation to MBSR and other contemporary practices needs some further work. Several recent studies have highlighted a lack of consistency in the way mindfulness is understood and thus operationalised. Perhaps this is the single biggest challenge meditation research faces today. If there is a weakness in the reliability over what mindfulness is, how it is understood, applied and taught, it makes experimental replication difficult. Without methodologically sound replication the building blocks to advance meditation research can’t be put in place. This I think is the main message from the Van Dam et al. review. Consider that the scientific investigation of meditation in the west is at least 45 years old, an estimated 15,000 meditation studies have been published in that time and yet experimental work is still often described as ‘preliminary’. What is the strategy to elevate meditation research to a more reliable footing?