Meditation-Related Brain Research and Its Treatment Implications
Tibetan Buddhist Loving Kindness Meditation
Antoine Lutz and colleagues studied eight long-term Tibetan Buddhist meditators who had engaged in contemplative practice for periods of time ranging from 15 to 40 years, with anywhere from approximately 10,000 to 50,000 hours logged in meditation (2004). A control group consisted of 10 students averaging 20 years of age, each of whom had only ten hours of training in meditation. The meditation technique studied in this case, a Buddhist loving kindness meditation, evokes a state of objectless compassion that is allowed to pervade the meditator's mind.
All meditators exhibited atypically large amounts of synchronized gamma activity 5 to 15 seconds after beginning the meditation, with significant asymmetrical gamma synchrony appearing in the left midfrontal areas. Analysis revealed that the long-term meditators showed greater such synchrony than controls, as well as higher baseline levels of gamma activity. Likewise, even among the long-term meditators, the ones with the most hours of meditative practice logged also exhibited the highest levels of gamma activity. Long-distance synchronization between frontal and parietal lobes also increased in all meditators, with the highest degrees of synchronization again being found to positively correlate with the number of hours logged in meditative practice. Using fMRI, there was also discovered significant activity in the thalamus, caudate and putamen, right insula, and anterior cingulate.
Buddhist Mindfulness Meditation
According to the Kentucky Inventory of Mindfulness Skills (KIMS: Baer, et al, 2004), mindfulness consists of nonreactivity to inner experience, attending to sensations and feelings, actions with awareness, labeling sensations and feeling states with words, and a non-judgmental attitude toward experience.
Sara W. Lazar and cohorts discovered this meditative practice to be correlated with increased cortical thickness in the middle prefrontal areas, as well as enlarged right insulas, in experienced practitioners (2005). Additional studies have revealed mindfulness practice and Mindfulness-Based Cognitive Therapy (MBCT) to animate neural structures involved in attention (Lazar, et al, 2000), serve as a viable treatment modality for ADHD (Zylowska, et al, 2008), counter the tendency toward diminished left-frontal activity in severe depression (Barnhofer, et al, 2007), and significantly reduce anxiety and depressive symptoms in bipolar affective disorder (Williams, et al, 2008). And according to Siegel, "[m]indfulness meditationappears to produce a left shift in frontal activation" (2007, p. 220).
These combined research data suggest that attentional training can induce both temporal and stable changes in neural firing patterns. The temporal changes evoked during meditative practice, such as the high occurrence of alpha and theta wave activity, are stably integrated into the brain's neural circuitry when practiced consistently over time. Such alpha and theta wave activity is believed to be indicative of states of inner calm and stability (Siegel, 115). Meditative discipline, then, appears to offer not only a hopeful treatment option for various mental, affective, and neural disorders, but a path for more fully developing the brain's potential as well.
Gamma Activity Implications
The increased gamma wave synchrony generated during Tibetan Buddhist loving kindnessmeditation may have applications in the treatment of disorders where feature binding has been found to be deficient. Because gamma activity has been repeatedly observed as active in perception and implicated in associative learning (Miltner, et al, 1999), it has been theorized that gamma wave synchrony may play a significant role in binding the disparate information conveyed by the central nervous system into coherent perception (Singer, 2001).
The fact that neuroscience still has not fully identified the neural correlates of such coherent perception has been referred to as the "binding problem" (Roskies, 1999). If gamma wave synchrony does in fact play a significant role in perception, this could explain why long-term practitioners of loving kindness meditation exhibit a readiness and willingness to compassionately respond to the interior experience-both positive and negative-of others. In other words, attentional training with compassionate embrace as its focus seems to developthe brain's capacity for unifying sensory information into coherent patterns of perception that support both personal and interpersonal connection. Such a sense of connection can be vital in the treatment of disorders like severe depression and schizophrenia, both of which involve a profound interior experience of isolation.
The lack of gamma wave activity during perception in schizophrenia in left and frontal sites (Haig, et al, 2000) has been postulated as being due to a shift in the binding of synchronous and divided activity, preventing neural integration of various areas of the brain (Bob, 2007). Moreover, attention has been decisively shown to be central to 40 Hz gamma activity, so that when external stimuli are not consciously attended to, gamma activity is not registered (Sokolov, 1999). Attentional training using techniques like the loving kindness meditation, which seem to systematically drive and educate the brain toward producing more gamma wave activity, may offer a new set of developmental tools with which to treat schizophrenia. Moreover, the fact that long-term meditators exhibited higher baseline gamma activity than controls attests to the intention in long-term Buddhist meditation to slowly but consistently integrate meditative temporal states into permanent traits. According to Lutz and co-workers (2004), their research findings are "consistent with the idea that attention and affective processes, which gamma-band EEG synchronization may reflect, are flexible skills that can be trained (Posner, et al, 1997)" (p. 16373).
Neurologist James H. Austin (2006) links the coherent firing of both the frontal and parietal lobes within the gamma ranges with the conventional view that such synchrony is indicative of behavioral acts, or the preparation thereof, thereby implying that such activity within the context of a loving kindness meditation may bespeak a practical readiness for compassionate action (50). This readiness to readily and practically express compassion has always been the main objective for such Buddhist practices. Austin goes on, within the same context, to link the simultaneous activation of the caudate and putamen, in addition to the long-distance gamma synchrony between the frontal and parietal lobes, with the formation of "habits at successively higher-level behavioral and cognitive levels" (50). Taken together, these data could point to meditative training as a means of highly unifying sensory information to the point of producing unitary-that is, harmonious-interpersonal perceptions and relations.
Left Frontal Asymmetrical Activation Implications
Heather Urry and colleagues (2004) correlated left prefrontal asymmetry, as evidenced in both the mindfulness and loving kindness forms of meditation, with eudaimonic well-being, defined by Siegel (2007) as enveloping "the psychological qualities of autonomy, mastery of the environment, positive relationships, personal growth, self-acceptance, and meaning and purpose in life" (p. 216). This left anterior activity has also been correlated with resilience, the capacity to rebound after particularly negative experiences (Davidson, et al, 2003), which would make mindfulness meditation a viable modality in the treatment of bipolar affective disorder, sufferers of which can experience great difficulty in rebounding after difficult depressive periods.
This article's weakness lies in the fact that, due to a lack of space, only a small portion of the research in the field was covered. Likewise, the treatment implications discussed were but a few of many that could be mentioned. However, because it is intended to be a short introduction to contemplative neuroscience, it should serve to foment further investigation into the growing literature substantiating the idea that plasticity allows the brain to be influenced toward optimal functioning-emotionally and cognitively-through consistent attentional training. The inference given by Lutz and colleagues, which was still in press when it was quoted by Siegel (2007), sums up the potential for contemplative discipline in the cultivation of well-being:
Many of our core mental processes such as awareness and attention and emotion regulation, including our very capacity for happiness and compassion, should best be conceptualized as trainable skills. The meditative traditions provide a compelling example of strategies and techniques that have evolved over time to enhance and optimize human potential and well-being. The neuroscientific study of these traditions is still in its infancy but the early findings promise to both reveal the mechanisms by which such training may exert its effects as well as underscore the plasticity of the brain circuits that underlie complex mental functions (p. 101-2).