More on the Neuroscience of Meditation

This series articles was posted in the Zaadz: Integral Post-metaphysical Spirituality group at Gaiam, or Zaadz, or whatever the hell that place is called these days. I'm including two of the posts from EdWord in that group - they revolve around neuroscience and meditation.

None of this is new information if you've been following the research in recent years, but it collects a couple of good studies and some definitions in one place.

Meditation & Neuroscience

theurj said Monday, 8:08 AM:

The underlying anatomical correlates of long-term meditation: larger hippocampal and frontal volumes of gray matter.

Neuroimage. 2009 Apr 15;45(3):672-8: Luders E, Toga AW, Lepore N, Gaser C. Laboratory of Neuro Imaging, Department of Neurology, UCLA School of Medicine, Los Angeles, CA 90095-7334, USA.

Although the systematic study of meditation is still in its infancy, research has provided evidence for meditation-induced improvements in psychological and physiological well-being. Moreover, meditation practice has been shown not only to benefit higher-order cognitive functions but also to alter brain activity. Nevertheless, little is known about possible links to brain structure. Using high-resolution MRI data of 44 subjects, we set out to examine the underlying anatomical correlates of long-term meditation with different regional specificity (i.e., global, regional, and local). For this purpose, we applied voxel-based morphometry in association with a recently validated automated parcellation approach. We detected significantly larger gray matter volumes in meditators in the right orbito-frontal cortex (as well as in the right thalamus and left inferior temporal gyrus when co-varying for age and/or lowering applied statistical thresholds). In addition, meditators showed significantly larger volumes of the right hippocampus. Both orbito-frontal and hippocampal regions have been implicated in emotional regulation and response control. Thus, larger volumes in these regions might account for meditators' singular abilities and habits to cultivate positive emotions, retain emotional stability, and engage in mindful behavior. We further suggest that these regional alterations in brain structures constitute part of the underlying neurological correlate of long-term meditation independent of a specific style and practice. Future longitudinal analyses are necessary to establish the presence and direction of a causal link between meditation practice and brain anatomy.
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Long-term meditation is associated with increased gray matter density in the brain stem.

Neuroreport. 2009 Jan 28;20(2):170-4: Vestergaard-Poulsen P, van Beek M, Skewes J, Bjarkam CR, Stubberup M, Bertelsen J, Roepstorff A. Center for Functionally Integrative Neuroscience, Aarhus University, Aarhus, Denmark. peterv@pet.auh.dk

Extensive practice involving sustained attention can lead to changes in brain structure. Here, we report evidence of structural differences in the lower brainstem of participants engaged in the long-term practice of meditation. Using magnetic resonance imaging, we observed higher gray matter density in lower brain stem regions of experienced meditators compared with age-matched nonmeditators. Our findings show that long-term practitioners of meditation have structural differences in brainstem regions concerned with cardiorespiratory control. This could account for some of the cardiorespiratory parasympathetic effects and traits, as well as the cognitive, emotional, and immunoreactive impact reported in several studies of different meditation practices.

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Re: Meditation & Neuroscience

theurj said Monday, 5:43 PM:

“Most of the neurological phenomena associated with religious experience involve some form of over-activation of the limbic system, and corresponding intensified experiences. Conversely, Alzheimer’s disease is associated with a deteriorization of the limbic system and those afflicted tend to lose interest in religion, even those who have exhibited a lifelong interest”

Skeptical Inquirer, 2006 Sep/Oct (Vol 30:Issue 5), p35-38. M. Spinella is an associate professor of psychology at the Richard Stockton College of New Jersey, USA. O. Wain is a graduate student in biomedical sciences at the University of Medicine and Dentistry of New Jersey, USA
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The second study above makes a direct reference to the brainstem. All of the brain structures in the first study relate to the limbic system. Here’s an intro to this system from about.com:

The limbic system is a set of evolutionarily primitive brain structures located on top of the brainstem and buried under the cortex. Limbic system structures are involved in many of our emotions and motivations, particularly those that are related to survival. Such emotions include fear, anger, and emotions related to sexual behavior. The limbic system is also involved in feelings of pleasure that are related to our survival, such as those experienced from eating and sex.

Certain structures of the limbic system are involved in memory as well. Two large limbic system structures, the amygdala and hippocampus play important roles in memory. The amygdala is responsible for determining what memories are stored and where the memories are stored in the brain. It is thought that this determination is based on how huge an emotional response an event invokes. The hippocampus sends memories out to the appropriate part of the cerebral hemisphere for long-term storage and retrieves them when necessary. Damage to this area of the brain may result in an inability to form new memories.

Part of the forebrain known as the diencephalon is also included in the limbic system. The diencephalon is located beneath the cerebral hemispheres and contains the thalamus and hypothalamus. The thalamus is involved in sensory perception and regulation of motor functions (i.e., movement). It connects areas of the cerebral cortex that are involved in sensory perception and movement with other parts of the brain and spinal cord that also have a role in sensation and movement. The hypothalamus is a very small but important component of the diencephalon. It plays a major role in regulating hormones, the pituitary gland, body temperature, the adrenal glands, and many other vital activities.
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Here’s more info on it from wikipedia:

The limbic system is embryologically older than other parts of the brain. It developed to manage 'fight' or 'flight' chemicals and is an evolutionary necessity for reptiles as well as humans.

The limbic system (or Paleomammalian brain) is a set of brain structures including the hippocampus, amygdala, anterior thalamic nuclei, and limbic cortex, which support a variety of functions including emotion, behavior, long term memory, and olfaction.

The limbic system includes many structures in the cerebral cortex and sub-cortex of the brain.

The following structures are, or have been considered to be, part of the limbic system:

* Amygdala: Involved in signaling the cortex of motivationally significant stimuli such as those related to reward and fear in addition to social functions such as mating.
* Hippocampus: Required for the formation of long-term memories and implicated in maintenance of cognitive maps for navigation.
* Parahippocampal gyrus:Plays a role in the formation of spatial memory
* Cingulate gyrus: Autonomic functions regulating heart rate, blood pressure and cognitive and attentional processing
* Fornix: carries signals from the hippocampus to the mammillary bodies and septal nuclei.
* Hypothalamus: Regulates the autonomic nervous system via hormone production and release. Affects and regulates blood pressure, heart rate, hunger, thirst, sexual arousal, and the sleep/wake cycle
* Thalamus: The “relay station” to the cerebral cortex

In addition, these structures are sometimes also considered to be part of the limbic system:

* Mammillary body: Important for the formation of memory
* Pituitary gland: secretes hormones regulating homeostasis
* Dentate gyrus: thought to contribute to new memories and to regulate happiness.
* Entorhinal cortex and piriform cortex: Receive smell input in the olfactory system.
* Fornicate gyrus: Region encompassing the cingulate, hippocampus, and parahippocampal gyrus
* Olfactory bulb: Olfactory sensory input
* Nucleus accumbens: Involved in reward, pleasure, and addiction
* Orbitofrontal cortex: Required for decision making

There is some interesting discussion that follows these two initial posts, so go check it out.

Tags: Psychology, meditation, consciousness, brain, neuroscience, Gaiam, Integral Post-metaphysical Spirituality, underlying anatomical correlates of long-term meditation, hippocampus, Neuroimage, frontal cortex, gray matter, emotional regulation, response control, brainstem, limbic system