The brain plays a pivotal role in the study neurocognitive science. It is the seat of intelligence and is a complex organ which is being widely studied. Although mapping different areas of the brain has been carried a lot still remains for the study of cognition. Various non invasive modalities used for brain mapping are classified according to the measurement techniques used. Electromagnetic Technique uses two modalities for studying electromagnetic and electrical activity of the brain EEG

more »

... ctroencephalography) MEG (Magnetoencephalogrphy).Whereas hemodynamic technique uses recording of hemodynamic activity of the brain, these modalities are MRI (Magnetic Resonance Imaging). fMRI (functional Magnetic Resonance Imaging) PET (Positron Emission Tomography), SPECT (Single Photon Emission Computed Tomography) NRIS (Near Infrared Spectroscopy ). Hemodynamic techniques like MRI, fMRI, PET and SPECT provide excellent spatial resolution while electromagnetic modalities provide excellent temporal resolution .This paper explains various noninvasive modalities, their working principle and a comparative study of all the modalities.