In our investigations, we measure changes in the brain's blood flow, which correlates with brain activity. Our brain images show which parts of the brain are active and which parts are inactive during different states. For example, we compared the brain activity of people performing Tibetan Buddhist meditation to what their brains do at rest. Our studies, as well as those of other investigators, have shown that meditation increases activity in the front part of the brain and decreases activity in the area of the brain that orients our bodies in space. This increased frontal activity is found not only during meditation, but also during any attention-focusing task. Since meditation involves focusing attention, it makes sense that this attention area of the brain is activated. The decreased activity in the orientation area is believed to be related to the changes in spatial perception and the loss of a sense of self that are associated with meditative states. Future studies may help to better define the changes in the brain that occur during meditation.