Increased gray matter volume in the right angular and
posterior parahippocampal gyri in loving-kindness
Mei-Kei Leung,1,2Chetwyn C. H. Chan,3,4Jing Yin,4,5Chack-Fan Lee,4,5Kwok-Fai So,4,6,7and Tatia M. C. Lee1,2,4,7,8
1Laboratory of Neuropsychology, The University of Hong Kong, 852 Hong Kong, China,2Laboratory of Cognitive Affective Neuroscience,
The University of Hong Kong, 852 Hong Kong, China,3Applied Cognitive Neuroscience Laboratory, Department of Rehabilitation Sciences,
The Hong Kong Polytechnic University, 852 Hong Kong, China,4Social Neuroscience Research Network, The University of Hong Kong, 852 Hong
Kong, China,5Centre of Buddhist Studies, The University of Hong Kong, 852 Hong Kong, China,6Department of Anatomy, The University of
Hong Kong, 852 Hong Kong, China,7The State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, 852 Hong Kong,
China, and8Institute of Clinical Neuropsychology, The University of Hong Kong, 852 Hong Kong, China
Previous voxel-based morphometry (VBM) studies have revealed that meditation is associated with structural brain changes in regions underlying
cognitive processes that are required for attention or mindfulness during meditation. This VBM study examined brain changes related to the practice
of an emotion-oriented meditation: loving-kindness meditation (LKM). A 3T magnetic resonance imaging (MRI) scanner captured images of the brain
structures of 25 men, 10 of whom had practiced LKM in the Theravada tradition for at least 5years. Compared with novices, more gray matter volume
was detected in the right angular and posterior parahippocampal gyri in LKM experts. The right angular gyrus has not been previously reported to have
structural differences associated with meditation, and its specific role in mind and cognitive empathy theory suggests the uniqueness of this finding for
LKM practice. These regions are important for affective regulation associated with empathic response, anxiety and mood. At the same time, gray matter
volume in the left temporal lobe in the LKM experts appeared to be greater, an observation that has also been reported in previous MRI meditation
studies on meditation styles other than LKM. Overall, the findings of our study suggest that experience in LKM may influence brain structures associated
with affective regulation.
Keywords: temporo-parietal junction; voxel-based morphometry; metta meditation; empathy; affective regulation
It is well known that the human brain is a malleable organ. This sug-
gests that intense training can induce structural changes in brain
regions that are needed to produce the trained behavior (Draganski
and May, 2008). Indeed, scientists coined the term ‘neuroplasticity’ to
describe the fact that the human brain changes in response to experi-
ential learning. The classic study of London taxi drivers is one of the
best illustrations of experience-induced neuroplastic change. In their
study, Maguire et al. (2000) demonstrated that experience navigating
London streets was associated with significantly larger bilateral poster-
ior hippocampi. The hippocampus is known to be a spatial navigation
center (Maguire et al., 1998). Along similar lines, Aydin et al. (2007)
found that math experts have higher gray matter density in the parietal
cortex than did controls. In fact, the parietal cortex is known for its
involvement in arithmetic calculations and visuospatial processing
(Dehaene et al., 1999).
Meditation is a process of training mental states, and such experi-
ential learning may affect the human brain. Lazar et al. (2005) were the
first to investigate the relationship between meditation and structural
brain changes. They found that expert insight meditators had a thicker
prefrontal cortex and right anterior insula than novice meditators.
Since then, other studies have reported differences in brain structures
between experts and novices in a number of meditation practices,
including Zen (Pagnoni and Cekic, 2007; Grant et al., 2010), insight
(Ho ¨lzel et al., 2008), concentrative practices and open awareness
(Vestergaard-Poulsen et al., 2009) and a mixed style (Luders et al.,
2009). Zen experts have a thicker anterior cingulate cortex (ACC)
compared with novices (Grant et al., 2010). The ACC actively helps
people focus and refocus attention voluntarily in response to distrac-
tion and, thus, may help Zen meditators maintain their state of ‘emp-
tiness’ (Pagnoni et al., 2008). In insight experts, the right anterior
insula is cortically thicker than in novices (Lazar et al., 2005). The
insula is important for interoceptive awareness, which connects us
with our subjective internal states (Ho ¨lzel et al., 2008). Some studies
have reported that cortical thickness/gray matter volume is associated
with years/hours of meditation practice (Lazar et al., 2005; Ho ¨lzel et al.,
2008) while other studies have failed to identify any relationship
between these two variables (Luders et al., 2009; Vestergaard-Poulsen
et al., 2009).
In general, scientific studies have focused on types of meditation
that train attention regulation to produce a calm mind. Therefore, it
should be no surprise that they have found differences in the brain
regions in the attention system. Following this line of thought, medi-
tation that focuses on affective processing should have an effect on the
emotion-processing system. If meditation really can change how the
brain processes emotions, the finding could influence how clinicians
design interventions for clinical affective dysregulation.
Loving-kindness meditation (LKM) is a form of meditation that
trains emotion regulation. LKM practitioners explicitly cultivate posi-
tive feelings, generating an emotional state that is full of unconditional
love, compassion and empathy toward the self and others, without any
discursive thoughts (Salzberg, 1995). Previous research has shown that
a short LKM practice in the laboratory was sufficient to induce
Received 18 January 2012; Accepted 8 July 2012
Advance Access publication 18 July 2012
This work was supported by the May Endowed Professorship, a Research and Conference Grant (#10401362 to
T.L.), research funding from the Centre of Buddhist Studies of The University of Hong Kong (to T.L.) and the
Research Grant Council General Research Fund (HKU747612H to T.L.). There are no conflicts of interest including any
financial, personal or other relationships with persons or organizations for any author related to the work described
in this article.
Correspondence should be addressed to Tatia M. C. Lee, May Professor in Neuropsychology, Laboratory of
Neuropsychology, The University of Hong Kong, Room 610, Knowles Building, Pokfulam Road, Hong Kong, China.
doi:10.1093/scan/nss076SCAN (2013) 8, 34^39
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