Two new studies published in Frontiers
of Human Neuroscience showed that the brains of meditators are more
integrated than those who do not meditate. William Harryman wrote the observed
benefits of meditation are: (1) variations in insular complexity could affect
the regulation of well-known distractions in the process of meditation, such as
daydreaming, mind-wandering, and projections into past or future, (2) increased
insular gyrification may reflect an integration of autonomic, affective, and
cognitive processes, (3) participants with more meditation experience exhibited
increased connectivity within attentional networks, as well as between
attentional regions and medial frontal regions, and (4) these neural
relationships may be involved in the development of cognitive skills, such as
maintaining attention and disengaging from distraction, that are often reported
with meditation practice.
Several cortical regions are
reported to vary in meditation practitioners. However, prior analyses have
focused primarily on examining gray matter or cortical thickness. Thus,
additional effects with respect to other cortical features might have remained
undetected. Gyrification (the pattern and degree of cortical folding) is an
important cerebral characteristic related to the geometry of the brain’s
surface. Thus, exploring cortical gyrification in long-term meditators may
provide additional clues with respect to the underlying anatomical correlates
of meditation. This study examined cortical gyrification in a large sample (n
= 100) of meditators and controls, carefully matched for sex and age. Cortical
gyrification was established by calculating mean curvature across
thousands of vertices on individual cortical surface models. Pronounced group
differences indicating larger gyrification in meditators were evident within
the left precentral gyrus, right fusiform gyrus, right cuneus, as well as left
and right anterior dorsal insula (the latter representing the global
significance maximum). Positive correlations between gyrification and the
number of meditation years were similarly pronounced in the right anterior
dorsal insula. Although the exact functional implications of larger cortical
gyrification remain to be established, these findings suggest the insula to be
a key structure involved in aspects of meditation. For example, variations in
insular complexity could affect the regulation of well-known distractions in the
process of meditation, such as daydreaming, mind-wandering, and projections
into past or future. Moreover, given that meditators are masters in
introspection, awareness, and emotional control, increased insular gyrification
may reflect an integration of autonomic, affective, and cognitive processes.
Due to the cross-sectional nature of this study, further research is necessary
to determine the relative contribution of nature and nurture to links between
cortical gyrification and meditation.
Luders E, Kurth F, Mayer EA,
Toga AW, Narr KL, & Gaser C. (2012). The unique brain anatomy of
meditation practitioners: alterations in cortical gyrification. Frontier in
Human Neuroscience, 6:34. DOI: 10.3389/fnhum.2012.00034
This study
sought to examine the effect of meditation experience on brain networks
underlying cognitive actions employed during contemplative practice. In a previous
study, we proposed a basic model of naturalistic cognitive fluctuations that
occur during the practice of focused attention meditation. This model specifies
four intervals in a cognitive cycle: mind wandering (MW), awareness of MW,
shifting of attention, and sustained attention. Using subjective input from
experienced practitioners during meditation, we identified activity in salience
network regions during awareness of MW and executive network regions during
shifting and sustained attention. Brain regions associated with the default
mode were active during MW. In the present study, we reasoned that repeated
activation of attentional brain networks over years of practice may induce
lasting functional connectivity changes within relevant circuits. To investigate
this possibility, we created seeds representing the networks that were active
during the four phases of the earlier study, and examined functional
connectivity during the resting state in the same participants. Connectivity
maps were then contrasted between participants with high vs. low meditation
experience. Participants with more meditation experience exhibited increased
connectivity within attentional networks, as well as between attentional
regions and medial frontal regions. These neural relationships may be involved
in the development of cognitive skills, such as maintaining attention and
disengaging from distraction, that are often reported with meditation practice.
Furthermore, because altered connectivity of brain regions in experienced meditators
was observed in a non-meditative (resting) state, this may represent a
transference of cognitive abilities “off the cushion” into daily life.
Hasenkamp W, and Barsalou
LW. (2012). Effects of meditation experience on functional connectivity
of distributed brain networks.
Frontiers in Human Neuroscience, 6:38. DOI: 10.3389/fnhum.2012.00038
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