1Ways to Study Brain Structures and FunctioningCan physically trace connections• Is the most primitive• Can be done with any structuresAblation• Can remove a piece of the brain and see what happens• If the behavior changes, you can assume that part had some effect.• Occasionally done with epilepsy patients2Accidents, Tumors, Strokes• After they occur can look at changes in behavior.• Problem – The whole system can be affected.Electrical and Chemical Stimulation.Fritsch and Hitzig, later Penfield• Electrically stimulated the brain of humans in surgery and observed what happened. • Hands moved, thoughts were recalled, etc.• Commonly done today in neurosurgery -called brain mapping.• Reaction depends on where the needle is placed. • Can also use chemicals to stimulate the system.EEG (Electroencephalogram)• Used to record the electrical activity of the brain• Excellent for the diagnosis of epilepsy – Best when the person is asleep3MEG (Magnetoencephalogram)• Records the changes in magnetic fields produced by electrical activity in the brain.Angiogram• Used to examine blood vessels in the brain• Important to diagnose strokes and tumors• Can add contrast mediums (dyes)X - Rays•.Can use to view brain structures. • Important for examining ventricles and other structures• Not used as much today4CAT Scan or CT Scan (Computerized Axial Tomography or Computerized Tomography)• Provides a cross section X-Ray of the brain• Good to diagnose tumors and strokesPET Scans (Positron Emission Tomography)• Provides a picture of Brain Functioning • Monitors the amount of glucose (sugar) the brain is using.• Make the glucose radioactive• The more glucose you use, the more brain activity there is.MRI (Magnetic Resonance Imagery)Sets up a magnetic fieldCauses water molecules to vibrate, and changes ion structure.Allows you to get a good picture of brain structuresExcellent for diagnosis of Multiple Sclerosis.5SPECT Single-Photon Emission Computerized Tomography• Is similar to PET• Uses radioactively-tagged tracer• Resolution is lower• Is lower cost. Makes it more practical for widespread useSQUID Superconducting Quantum Interference DeviceVery newLike MRI – Senses changes in magnetic fieldsWhen nerves fire they create magnetic fieldsFields indicate neural activity.Found • The brain hears loud sounds in different placesthan quiet sounds• Areas were laid out like a piano keyboard.Distance between areas that hear low c and middle c is the same as middle c and high c• Place where the brain remembers faces is different from where it remembers objects.e.g. Faces were recalled in the right hemisphere that specializes in spatial configurationsObjects (spatula) Recalled in the cortex that originally processed how the spatula felt and the hands moved it. (Parietal Lobe)6Psychological Tests of Brain Functioning• Halstad-Reitan• Contains a variety of sub-tests– Most tasks are simple and can be easily done by normal people – With eyes close, individual is asked, “Which hand am I touching?”– Identify the number that has been traced on a finger.– Also have a lot of more complicated tests• Aphasia Screening test• WAIS-IIILuria-Nebraska• Has 269 discrete items in several categories.• Includes categories such as – Tracing objects on wrist– Motor coordination• Strong reliability and validity– >80% or better on identification of brain damaged subjectsOther Tests• Porteus Mazes– Get out of mazes. – Look at errors and time to get out.• Bender Gestalt– Give a picture and have the person draw it.• Line Orientation tests– Which line is oriented with the stimulus