“If you have ever participated in an fMRI experiment, the rush you felt when you saw your brain in action for the first time is something you will never forget. First, you had to lie absolutely still inside a claustrophobic, coffin-like enclosure while, to the nonmusical accompaniment of metallic clanks and bangs, a succession of images and words like dog, cat, box, run, swim, and grab were presented to you. Then, when it was finally over, you stepped out of the torture chamber, stretched, and made your way to the control room. There, with the press of a button, the researcher generated an image of your thinking brain. Not only were you relieved to discover that, yes, you really do have a brain, but you were astonished to behold visible proof that the chunk of meat actually thinks. (Berent, 178)”
Neuroimaging: includes techniques such as positron-emission tomography (“PET”) scans and functional magnetic resonance imaging (fMRI) scans that allow scientists to go beyond snapshots and see the brain at work. (Ratey, 129) Used for both descriptive and experimental research. Used in “cognitive neuroscience.” Most brain-imaging studies involve a small groups of subjects. Most involve simple aspects of behavior. Knowing what brain area is involved may tell us little about the psychological process being investigated. (Hockenbury, 60) Neuroimaging allows us to ask two fundamental questions about every part of the brain: What does it look like? What does it do? (Grandin, 22)
Functional Magnetic Resonance imaging (fMRI): imaging technique that tracks the flow of "oxygenated" blood by virtue of its magnetic properties, which differ from those of non-oxygenated blood. Because oxygenated blood preferentially flows to where it is in high demand, fMRI highlights brain areas that are most active when someone is thinking or doing something. (SAM, Oct/Nov 2007, 42) In fMRI, magnetic fields in the brain produced by changes in blood flow are measured while the subject is doing or looking at something. (RamachandranTTB, 61) Images are called 'functional' because they measure how the brain performs tasks rather than simply mapping out the structure of the brain. (Spinks) Technique yields the equivalent of a video showing what parts of the brain light up during different inputs, or imagery. (Goleman, 10) It is possible to use fMRI non-invasively to track the activity of the whole brain while subjects are performing a variety of tasks. It has good, although not ideal, “spatial” and temporal resolution, but not down to the single cell achieved with implanted electrodes in experiments with monkeys. (Iacoboni, 60) Provides moment to moment images of the brain’s changing activity using the same scanning hardware as an “MRI.” Compared to PET scans, fMRI produces a much sharper picture and can detail much smaller brain structures. Another advantage of fMRI is that it provides a picture of brain activity averaged over seconds rather than the several minutes required by PET scans. (Hockenbury, 60) (In an fMRI), one area of your brain (might) respond to nouns and another to verbs. It’s not just nouns and verbs. Scientists can capture images of your emotional brain in action, your moral brain, or your brain on music. You can see your brain in comtemplation of a beautiful artwork, or recoiling from a disgusting image. (Berent, 178)
Magnetic Resonance Imaging (MRI): a noninvasive imaging technique that produces highly detailed images of the brain using electromagnetic signals generated by the brain in response to magnetic fields. MRI is very versatile, producing 'thin-slice' images of body tissue from virtually any angle. Tissues with high concentrations of water, such as fat, appear lighter in color, while bone and other tissues with less water appear darker. (Hockenbury, 60)
Diffusion Tensor Imaging (DTI): new MRI approach that tracks water “diffusion” along nerve fibers, exposing the micro architecture of the brain. Can show physical connections between brain structures. (SAM, Dec 2007/Jan 2008, 8) Also referred to as ‘diffusion MRI.’
Magnetocephalography (MEG): modern neuroimaging technique which relies on the principle that if you touch different body parts, the localized electrical activity that results can be measured as changes in magnetic fields on the scalp. The major advantage of the technique is that it is noninvasive; one does not have to open the patient’s scalp to peer inside the brain. Using MEG is relatively easy in just a two-hour session to map out the entire body surface on the brain surface of any person willing to sit under the magnet. (Ramachandran, 31)
Positron Emission Tomography (PET scan): an imaging test of the brain. It uses a radioactive substance called a ‘tracer’ to look for disease or injury in the brain. A PET scan shows how the brain and its tissues are working. Other imaging tests, such as MRI and CT scans only reveal the structure of the brain. (PubMedHealth2) An invasive imaging technique that provides color-coded images of brain activity by tracking the brain’s use of a radioactively tagged compound, such as “glucose,” “oxygen,” or a drug. The PET scan measures the amount of the radioactively-tagged-substance used in brain areas while the person engages in some type of mental activity. Over the course of several minutes, the information is collected, analyzed, and averaged by computer. (Hockenbury, 60)
Single Photo Emission Computerized Tomography (SPECT scan): research technique where a patient is injected with a radioactive isotope that is carried by the blood to active brain areas. A special camera is then used to photograph the isotope's distribution. (SAM, Oct/Nov 2007, 41)