Summary to be used with some of the chapters of the book Principles of Cognitive Neuroscience by Purves, 2nd edition. The goal of cognitive neuroscience is to use the function of the brain and the nervous system to explain cognition and behaviour. Cognitive psychology pointed out the importance of measurement during cognitive and perceptual tasks to investigate neural activity is converted to action, thought and behaviour. Neuroscience has two categories (Figure 2.1 on page 19). The first is researching changes in cognitive behaviour when the brain has been stimulated, for example by trauma, medication or electronic stimulation. The other category is measuring brain activity when carrying out tasks using electrophysiological and imaging techniques. X-ray techniques have been used for a long time to make non-invasive images of the human body. Contrast agents can be injected to enhance the contrast of the picture. The first technological use of this was computerized tomography (CT) (Figure A on page 22). A CT uses X-rays to gather intensity information from multiple angles. The data can be viewed in ‘slices of tissue’, called tomograms.Magnetic Resonance Imaging (MRI, figure B on page 23) is faster and cheaper than CT. MRI uses strong magnets to ‘feed’ energy to protons in the water of the cell tissue, which move in the frequency of radio-wavelength. When the magnet is turned off, the protons in the body release the energy. The scanner measures excitation of energy by the protons. The proton density differs...