Gamma waves may be meditation's tool for changing the brain

Gamma_wavesLong-term meditators know that meditation can change people’s experience of the world, usually for the better. Highly experienced practitioners of meditation often report greater feelings of equanimity, patience, and compassion for others – even at times when they’re not meditating, such as during the workday or at dinner with family. Now researchers at the University of Bonn in Germany say they have an explanation for the new states of consciousness that arise as a result of meditation – gamma brain wave states, associated with expert-level meditation, assist in the reshaping of brain structures that persist beyond actual periods of meditation.

Brain researchers Jürgen Fell, Nikolai Axmacher, and Sven Haupt, in an August 2010 paper published in Medical Hypotheses, report that a survey of meditation research suggests a quantifiable difference between meditation’s effects on beginners and its benefits for experts. Upon initiating meditation training, beginners’ electroencephalogram (EEG) readings show slowed-down alpha wave states, an effect often seen when people are increasing their attention and focus during everyday activities. Theta wave activity is also often increased, under normal circumstances a sign of drowsiness and the beginning stages of sleep. Brain wave states for novice meditators, then, seem to reflect patterns also seen during prosaic human activities like concentrating and resting.

However, EGG readings for expert meditators (those who have practiced rigorously for years or decades) show something quite different: high-frequency gamma waves, sometimes thought to play a role in assimilating perceptions, are sharply increased. This certainly distinguishes expert meditators from their novice counterparts. But perhaps the most interesting finding is that gamma wave readings are also higher even when the experts aren’t meditating. This means that something about how advanced meditators experience the world appears to be fundamentally different, both during meditation and everyday activities, from how non-meditators or beginners experience it.

Backing up the suggestion that long-term meditation alters people’s ways of experiencing the world is data showing that expert meditators often boast increased cortical thickness and more gray matter in specific parts of their brains, meaning that their physical brains may have changed after all those years of meditating. Interestingly, gamma wave activity is thought to be associated with a phenomenon known as “neuroplasticity,” or the ability of the brain to form new connections and build on preexistent structures. This connection helps meditation researchers’ hypotheses fit with a fundamental tenet of neuroscience: that all unique states of consciousness are associated with unique brain states. Under this model, altered physical brain structures allow advanced meditators to experience novel states of consciousness.

While meditation research has exploded in recent years, there is still much work to be done. For example, many researchers are beginning to investigate how different meditation styles lead to different states of consciousness. Fell, Nicholai, and Haupt suggest in their article that many different meditation traditions lead to similar increases in gamma activity, but how such shifts are effected is still a mystery. The Bonn researchers hope their hypotheses will help others scientists to better categorize levels of meditation accomplishment, thus leading to new ideas for investigating these and other questions in the future.