Richard J. Davidson and Antoine Lutz
Buddha’s Brain: Neuroplasticity and Meditation
n a recent visit to the United States, the Dalai Lama gave a speech at the Society for Neuroscience’s annual meeting in Washington, D.C. Over the past several years, he has helped recruit Tibetan Buddhist monks for— and directly encouraged—research on the brain and meditation in the Waisman Laboratory for Brain Imaging and Behavior at the University of WisconsinMadison. The findings from studies in this unusual sample, as well as related research efforts, suggest that over the course of meditating for tens of thousands of hours, the long-term practitioners had actually altered the structure and function of their brains. In this article we discuss neuroplasticity, which encompasses such alterations, and the findings from these studies. Further, we comment on the associated signal processing (SP) challenges, the current status, and how SP can contribute to advancing these studies. WHAT IS NEUROPLASTICITY? The term neuroplasticity is used to describe the brain changes that occur in response to experience. There are many different mechanisms of neuroplasticity, ranging from the growth of new connections to the creation of new neurons. When the framework of neuroplasticity is applied to meditation, we suggest that the mental training of meditation is fundamentally no different than other forms of skill acquisition that can induce plastic changes in the brain , . WHAT IS MEDITATION? The term meditation refers to a broad variety of practices, ranging from techDigital Object Identifier 10.1109/MSP.2007.910429
niques designed to promote relaxation to exercises, performed with a more farreaching goal such as a heightened sense of well-being. It is thus essential to be specific about the type of meditation practice under investigation. In , meditation was conceptualized as a family of complex emotional and attentional regulatory strategies developed for various ends, including the cultivation of well-being
Buddhist Vipassan¯ and Mah¯ mudr¯ , a a a and are also implicated in many popular secular interventions that draw on Buddhist practices. FINDINGS OF BRAIN CHANGES IN MEDITATION In what follows, we summarize the changes in the brain that occur during each of these styles of meditation practice. Such changes include alterations in patterns of brain function assessed with functional magnetic resonance imaging (fMRI), changes in the cortical evoked response to visual stimuli that reflect the impact of meditation on attention, and alterations in amplitude and synchrony of highfrequency oscillations that probably play an important role in connectivity among widespread circuitry in the brain. EXPERIMENTAL SETUP The experiments described below that measure hemodynamic changes with fMRI require a high-field-strength magnetic resonance imaging (MRI) scanner equipped with the appropriate pulse sequences to acquire data rapidly and with the necessary fiber optic stimulus delivery devices so that visual stimuli can be presented to the subject while he or she lays in the bore of the magnet. For the studies that measure brain electrical activity, a high-density recording system with between 64 and 256 electrodes on the scalp surface is used. FA MEDITATION A recent study  used fMRI to interrogate the neural correlates of FA (continued on page 172)
THE TERM NEUROPLASTICITY IS USED TO DESCRIBE THE BRAIN CHANGES THAT OCCUR IN RESPONSE TO EXPERIENCE.
and emotional balance. Here we focus on two common styles of meditation, i.e., focused attention (FA) meditation and open monitoring (OM) meditation. FA meditation entails voluntarily focusing attention on a chosen object in a sustained fashion. OM meditation involves nonreactively monitoring the content of experience from moment to moment, primarily as a means to recognize the nature of emotional and cognitive patterns. OM meditation initially involves the use of FA...