Images of the working brain: understanding human brain function with positron emission tomography

In the past 15 years positron emission tomography (PET) has become a settled method of imaging the functioning human brain, both in normal volunteers and in patients with various disorders. Much of the work on sensory systems has been on the visual system, a conveniently studied and very important part of the brain. The motor system in health and disease has attracted as much interest. In this short review I will explain some of the technical aspects of PET, and illustrate some of the research that has been done on visual and motor brain function in the human.