Psychology Mr. Duez Unit 2 - Biological Bases of Behavior Brain Scans

5 PRIMARY WAYS TO EXAMINE THE BRAIN. EEG CT PET MRI fMRI STRUCTURE & ACTIVITY

EEG - Electroencephalograph EEG measures brain waves/electrical activity Seen a lot on sleep studies. With skull cap or individual electrodes - can measure brain activity

EEG - Electroencephalograph Although not a "brain scan" as the term is usually used, one of the first -- and still very useful -- ways of non-invasively observing human brain activity. Records electrical signals from the brain made by hooking up electrodes to the subject's scalp. The pens trace the signals onto the graph paper. State: asleep, awake, anaesthetized -- because the characteristic patterns of current differ for each of these states. Shows how long it takes the brain to process various stimuli. Major drawback - cannot show us the structures and anatomy of the brain or really tell us which specific regions of the brain do what.

CT/CAT SCAN - Computed Tomography Uses x-rays to create a 3 dimensional image. Nice view of soft tissue as well as denser bone structure.

CT/CAT SCAN Uses computer-processed X- rays to produce tomographic images or 'slices' - cross- sectional images are used for diagnostic and therapeutic purposes in various medical disciplines. Digital geometry processing is used to generate a three- dimensional image of the inside of an object from a large series of two- dimensional X-ray images taken around a single axis of rotation.

PET SCAN - Positron Emission Tomography Radioactive glucose to see functioning in the brain. Functioning - where is activity occurring in the brain?

PET SCAN - Positron Emission Tomography

PET scan below shows 2 areas of the brain (red & yellow) that become particularly active when volunteers read words on a video screen: the primary visual cortex & an additional part of the visual system, both in back of the left hemisphere. Other brain regions become especially active when subjects hear words through a headset, as seen in the PET scan on the right.

MRI - Magnetic Resonance Imaging Magnets/radio waves to see structure of the soft tissue.

MRI - Magnetic Resonance Imaging Sequential sections from an MRI of the brain, concurrently showing slices through transverse, sagittal, and coronal planes (left to right). MRI makes use of the property of nuclear magnetic resonance (NMR) to image nuclei of atoms inside the body. MRI can create more detailed images of the human body than are possible with X-rays.

fMRI - Functional Magnetic Resonance Imaging Functional neuroimaging procedure using MRI technology that measures brain activity by detecting associated changes in blood flow. This technique relies on the fact that cerebral blood flow and neuronal activation are coupled. When an area of the brain is in use, blood flow to that region also increases. Since the early 1990s, fMRI has come to dominate brain mapping research because it does not require people to undergo shots, surgery, or to ingest substances, or be exposed to radiation.

These fMRI images are from a study showing parts of the brain lighting up on seeing houses and other parts on seeing faces. The 'r' values are correlations, with higher positive or negative values indicating a better match.

5 PRIMARY WAYS TO EXAMINE THE BRAIN. EEG CT PET MRI fMRI STRUCTURE & ACTIVITY