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Electrodes adhere to the surface of the scalp or to the brain (in animals only)There is a lot of cortical activity, and the electrodes are able to measure the activity of the neurons in the cortexEEG testing has contributed to the discovery of sleep stages and important epilepsy researchProvides a picture of what is happening in the brainoCT/CAT: Only provides structural informationTakes an x-ray of the brain by sending rays into the brain and detecting how much of those rays were absorbed by the headX-rays contain radiationYou only get a horizontal image of the brain from a CT scanMedium resolutionoMRI: Only Provides structural informationDetects radio waves of H atomsCreates magnetic fields that cause H protons to line up into straight lines. Then, a wave knocks them out of place. As the protons try to line up again, the emit radio waves that are detected to create a sagittal view of the brain.An MRI creates higher resolution images than a CT scanoPET: Structural and FunctionalDone by injecting the brain with radioactive glucoseMore active portions of the brain will take up the glucose faster than less active portions. When neurons take up the radioactive glucose, the emit positron, which is detected by scanners which can then create a real time image of the brain and its activity levelsUsed to track changes in brain activity13
ofMRI: Structural and FunctionalMeasures changes in oxygen flow within the brain to see which areas are receiving moreblood and are, therefore, more activeSame as an MRI but with the added benefit of seeing brain functionImportant for the study of cognitive psychologyoMEG: Structural and FunctionalWhen neurons fire, there is electrical activity and they create small magnetic fieldsMEG measures the small changes in magnetic fields within the cortexThis indicates functional informationCreates real time 3-Dimensional maps that can look at all planes Stereotexic SurgeryoThis is the first step in all invasive physiological and pharmacological research techniquesoStep One: Use a Stereotexic Atlas to determine the location of the target area within the brainThe stereotaxic atlas gives 3 coordinates based on the anterior/posterior, medial/lateral, and ventral/dorsal coordinate planesoStep Two: Put the rat in the stereotaxic apparatusCut the scalp of the anesthetized rat openThe stereotaxic apparatus has two arms to hold the head and a bite arm that keeps the rat from hurting itself in the even that it wakes up during the surgery. It also has adjustingknobs for each of the three coordinate planesoStep Three: After adjusting for the coordinates, drill a hole in the rat’s skulloStep Four: Use the arm to lower the electrode onto the location of interestoStep Five: Anchor the electrode with dental acrylic oStep Six: Euthanize the rat and look at the brain to see if you hit the mark that you were initially aiming to hit by staining the brain slice of interest.