Holzel et al. (2011) — Mindfulness and brain scans

phrenology

the assumption that scalp morphology (structure) can be informative of the under lying brain function

mindfulness

a state achieved through meditation that aims to increase awareness of the present moment experience and enable a person to look at themselves in a compassionate, non-judgemetal way

What can an MRI calculate? (2)

- size of different structures

- the amount of grey matter compared to white matter

What is a strength of an MRI?

can detect small structural changes in the concentration of grey matter over time

What is the background of this study? (2)

- studies have compared individuals who engage in different kinds of meditation and those who do not

- have found differences in grey matter that appear to be associated with meditation

Criticism of the background of the study? (1)

Possible that brain differences found between groups was caused by pre-existing differences between the participants

Localisation of function

parts of the brain associated with particular types of information processing or with specific activities

What is the motor cortex responsible for?

deliberate movements

What is the somatosensory cortex responsible for?

skin and muscle sensation

What are Broca's and Wernicke's areas responsible for?

language functions

What is part of the brain stem responsible for?

sleep

What does it mean for many brain areas to be bilateral?

found in both left and right sides/hemispheres

Where are the motor and somatosensory cortex found?

both sides of the brain

Where are Broca and Wernicke's areas found?

left hemisphere

What are the 2 basic types of brain scan?

- functional

- structural

What does the functional type of brain scan do?

shows activity levels in different areas of the brain

What does the structural type of brain scan do?

takes detailed pictures of the shape of brain areas

What is the hippocampus associated with? (3)

- memory and navigation

- emotion and the arousal and responsiveness of the cortex

- determine which of many incoming sources we find stimulating

Plasticity

capable of creating new neurons and many new synapses between neurons.

What happens to the hippocampus after negative emotional experiences?

volume decreases

What happens to the hippocampus after treatment with antidepressant drugs?

volume increases

What are the advantages of mindfulness (2)

- appreciate simple positive experiences such as smells, sounds or sights and to notice when we are becoming anxious, stressed or depressed

- self-awareness enables us to act earlier/more effectively to reduce the problems

What is mindfulness facilitation?

formalised way to improve mindfulness — typically involves being silent and directing attention to oneself (eg. focussing on our own thoughts, sensations and sounds, such as breathing)

What is the aim of this study?

To identify changes in specific brain regions, and the whole brain, by comparing grey matter concentration before and after a mindfulness course.

What is the hypothesis?

MBSR intervention will have an effect on grey matter concentration in brain areas that play roles in learning, memory, self-referential processing, emotions and considering the viewpoints of others.

What are the research methods involved?

- longitudinal experiment

- self-report questionnaires

What is the experimental design?

independent measures

What is the independent variable?

exposure to an 8-week mindfulness-based intervention (the MBSR course)

What is the dependent variable?

the change in grey matter (measured using MRI scans)

What was the sampling technique? (2)

- volunteer sampling

- some referred by doctor

Where were the participants recruited from? (2)

- people already enrolled on MBSR courses at University of Massachusetts

- enrolled for help with stress reduction

Size of participating sample? (3)

- initial sample size was 8 males and 10 females

- 2 males left after first MRI session due to discussion

- final size 6 males and 10 females

What was the mean age of the final participating sample? Standard deviation?

- 38 years

- standard deviation was 4.1 years

What were the races of the final participating sample? (4)

- 13 Caucasian

- 1 Asian

- 1 African-American

- 1 multi-ethnic

Size of the control sample? (2)

- 7 males

- 10 females

What was the mean age of the control sample? Standard deviation? (2)

- 39 years

- standard deviation 9.2 years

What were the races of the control sample? (4)

- 13 Caucasian

- 2 Asians

- 2 African-Americans

- 1 Hispanic

What are the controlled variables? (5)

- participants physically and psychologically healthy and not taking medication

- limited experience of meditation

- aged 25 - 55 years

- considered safe to have an MRI scan

- committed to attend all sessions and complete the homework exercises

What was the procedure? (4)

- participating group and control group undergo an MRI scan before and after

- participating group and control group take the Five Facet Mindfulness Questionnaire (FFMQ) before and after

- the participating group attend 2 and 1/2 hour sessions every week for 8 weeks and 1 full day session on the 6th week — trained in mindfulness exercises

- participants would report the time spent on formal homework exercises over the 8 weeks and the amount of time spent on each of the 3 exercises

What does the FFMQ (Five Facet Mindfulness Questionnaire) measure? (5)

- observing (internal and external stimuli)

- describing (observations)

- acting with awareness (nothing done automatically/absently)

- non-judging (of inner experience)

- non-reactivity (to inner experience)

How was data gathered from the FFMQ? (3)

- closed questionnaire — 5 point Likert-type scale

- total score for each of 5 sub-scales added up for a total FFMQ score

- in each group, 14 participants provided useable data at both time points

When did the participating group do their MRI scans?

In the 2 weeks before and 2 weeks after the 8 week intervention (average 56 day gap)

When did the control group do their MRI scans?

66 days average gap between first and last

What were the 3 exercises the participating groups completed?

- body scan

- mindful yoga

- sitting meditation

What were the regions of interest produced from the MRI scans? (2)

- bilateral hippocampus

- bilateral insulae

What was the MRI used to produce? (2)

- regions of interest

- whole brain analysis

Average time participants spent on homework?

22.6 hours during the course / 27 minutes per day

Correlation coefficient between body scan and sitting meditation?

r = -0.26 (NOT SIGNIFICANT)

Correlation coefficient between yoga and sitting meditation?

r = 0.49 (NOT SIGNIFICANT)

What were the results in terms of the participating and the questionnaire?

Participants in the MBSR group significantly increased their mindfulness scores on 3 sub scales (acting with awareness, observing, non-judging) between the first and last questionnaire

Differences in grey matter concentration in the left hippocampus BETWEEN CONTROL GROUP AND PARTICIPATING GROUP at the BEGINNING?

no differences

Differences in grey matter concentration in the left hippocampus in the control group between first and second test?

No difference

Was there a difference in grey matter concentration in the left hippocampus in participating group between first and second test?

- there were changes

- but the changes did not correlate with amount of homework completed or changes in the FFMQ scores

Were there changes in areas of interest other than the left hippocampus?

no other significant changes

What were the results from the whole brain analysis in the participating group?

- 4 clusters in the brains of participants were found to have significantly increased grey matter concentration between first and second test

Where were the 4 clusters that increased found? (4)

- posterior cingulate cortex

- left temporal-parietal junction

- lateral cerebellum

- cerebellar vermis/brainstem

What was the correlation between the changes in the 4 clusters that increased and the amount of homework completed/changes in the FFMQ scores?

no correlation

Were there any decreases in grey matter concentration in either group?

- none in the participating group

- some small reductions in the control group

What are the conclusions of the experiment in regards to the left hippocampus? (3)

- structural changes in the left hippocampus arise within an 8 week period of participation in a mindfulness course

- this suggests that increases/decreases in hippocampal volume may happen in response to mindfulness meditation

- the hippocampus plays a role in learning and memory and so suggests that during the course, participants had learning experiences that changed the hippocampal grey matter

What are the conclusions of the experiment in regards to the temporo-parietal junction (TPJ), posterior cingulate cortex (PCC), and cerebellum?

participation in an 8 week mindfulness course changes the structure of the left temporo-parietal junction (TPJ), posterior cingulate cortex (PCC), and cerebellum

Why is it significant that there was a change in part of the cerebellum?

One of the areas identified as changing has a role in regulating emotions and cognition for healthy psychological functioning.

What were the ethical strengths? (3)

- right to withdraw: 2 males left after 1st MRI scan

- informed consent

- everyone was considered safe to have MRI scans (no metal, no claustrophobia — protection from harm)

What were the ethical failures?

the participants relegated to control group were experiencing help and were delayed in receiving help — failure to protect from harm (however it could be beyond researchers' control because it is unknown if there was a max. capacity)

What are the strengths of the study? (4)

- longitudinal study — tested before and after lengthy intervention to allow experience to affect brain plasticity in a measurable way

- control group — allows comparison

- MRI scan produces objective data

- not possible for demand characteristics (cannot change grey matter)

What are the limitations of the study? (5)

- many unknowns about localisation of specific behaviours in the brain and the meaning of changes in volume

- interpretation of data with respect to neural changes and how it affects thoughts/emotions is not as objective

- absence of correlation with grey matter changes and homework completed/changes in FFMQ score — no cause-effect relationship

- need control group to participate in same course but without the mindfulness aspect to isolate effects of mindfulness meditation

- MRI is not ecologically valid — noisy and confining