Brain mapping is a group of techniques where normal or abnormal activities of the brain can be projected as spatial representations called as maps. A variety of techniques and therefore a number of physiological principles are operational in brain mapping techniques. These include some older methods such as mapping the electrical activity by electroencephalography or electrocorticography. Computerised tomography though offers a three dimensional picture by projecting focused x-ray beams has the disadvantage of depicting mostly the structure of the brain. Therefore newer methods like positron emission tomography [PET]and functional MRI give an idea of the actual spatial organisation during cerebral activity. These methods are based on the principle that cerebral blood flow alters as a result of function and therefore methods which pick up and map alterations in blood flow can help in neurophysiological studies or help us comprehend the progression of disease. Many novel methods like immunohistochemistry which can track antigen antibody reactions in specific cerebral areas or nanotechnology which can track atoms within neurotransmitters can help us map and study brains functions as well as abnormality more precisely. Research is ongoing in these areas for the early detection and management of many neurodegenerative and psychiatric disorders. This article attempts to give an overview of the various brain mapping techniques in their order of discovery, the drawbacks or advantages of individual methods and the physiological concepts behind the same.