Brain Imaging

Brain imaging (neuroimaging) techniques are used on patients to analyse the activity or problems within the human brain, without invasive neurosurgery.  Functional magnetic resonance imaging (fMRI), measures brain activity and works by detecting the changes in blood flow oxygenation and results in response to neural activity.  Computed tomography (CT) scanning builds up an image of the brain based on the differential absorption of x-rays.  CT scans reveal the significant features of the brain but do not resolve its structure well. Positron Emission Tomography (PET) uses short-lived radiotracers to map functional processes in the brain.  The regions of high radioactivity are associated with brain activity.  Electroencephalography (EEG) measures the electrical activity of the brain by recording from electrodes placed on the scalp. The electroencephalogram (EEG) represents an electrical signal from a large number of neurons.  Magnetoencephalography (MEG) measures the magnetic fields generated by electrical activity in the brain via susceptible devices known as SQUIDs (Superconducting QUantum Interference Devices). The optical technique near-infrared spectroscopy measures blood oxygenation in the brain.