1. How Psychologists Study the Brain
Module One: Booklet 6

2. Physiological Psychologists
Also called psychobiologists
Psychologists who map the brain’s fissures (grooves on the brain which appear as a deep fold) and inner recesses
Method include:
1) Recording
2) Stimulating
3) Lesioning
4) Imaging

3. 1) Recording
Electrodes inserted into the brain to record electrical activity
Recall the brain generates enough electricity to power a low-wattage light bulb!
Possible to detect minute (small) electrical changes that occur when neurons (brain cells) fire
EEG (electroencephalograph) records electrical activity of whole areas of the brain

4. Have found that overall electrical activity of the brain rises ad falls rhythmically and that the pattern of the rhythm depend on whether a person is awake, drowsy, or sleepy
Rhythms(brains waves), occur because the neurons in the brain tend to increase or decrease their amount of activity in unison (together)

5. 2) Stimulation
Electrodes used to set off (cause) the firing of neurons (brain cells)
Brain surgeon Wilder Penfield stimulated the brains of his patients during surgery to determine what functions the various parts of the brain perform so as to localize (focus on) the malfunctioning part for which surgery was required

6. Stimulation techniques have been used with terminal cancer patients to relieve intolerable pain without using drugs and experiments done to control violent emotional behaviours in uncontrollable patients

7. 3) Lesions (any abnormality in the tissue of an organism (i. e
3) Lesions (any abnormality in the tissue of an organism (i.e."damage"), usually caused by disease or trauma)
Scientists sometimes create lesions by cutting or destroying part of an animal’s brain.
If the animal behaves differently after the operation, they assume that the destroyed brain area is involved with that type of behaviours
Psychologists can learn from tragedies when some people suffer accidents which involve the brain

8. Psychobiologists try to draw a connection between the damaged parts of the brain and a person’s behaviours, such as Phineas Gage in 1848

10. 4) Images
Psychobiologists use PET scans, CAT scans and MRI scans

11. A) PET scans Means Positron emission tomography
Captures a picture of the brain as different parts are being used
Involves injecting a slightly radioactive solution into the blood and then measuring the amount of radiation absorbed by brain cells

12. Active neurons absorb more radioactive solution than a nonactive one
Used to see which areas are being activated while performing a task

13. Did You Know...
About 1 hour after the injection, the PET scan is done.
The PET scanner looks like a large, doughnut-shaped scanner, similar to a CT scanner.
The person sits or lies down on the exam table and is asked to stay very still.
Sometimes PET scan can be done along with CT or MRI.
After the scan, the radioactive material quickly loses its radioactivity. It passes out of the body through the urine or stool (feces)

14. b) CAT scans (or CT scan)
Means computerized axial tomography
Used to pinpoint injuries and other problems in brain deterioration (ex. Alzheimer's Disease)
During scan, a moving ring passes x-ray beams around and through a subject’s head

15. Radiation is absorbed in different amounts depending on the density (“weight”) of the brain tissue
Computers measure the amount of radiation absorbed and transform this information into a three-dimensional view of the brain

17. Did You Know...
A computed tomography (CT) scan is an imaging test that uses a computer to put a series of special x-ray images together to create detailed 3-dimensional images of organs, tissues, bones and blood vessels in the body. Some CT scans require a contrast medium to show organs and abnormalities more clearly.
A CT scan is also called computerized axial tomography (CAT) scan.
A CT scan can be done on almost any body part. It can show detailed views of many different types of tissue, such as the: brain, airways, lungs, bones, soft tissue and blood vessels

18. C) MRI scans Means magnetic resonance imaging
Enables researchers to study both activity and brain structures
Combines features of both PET and CAT scans
Involves passing nonharmful radio frequencies through the brain

19. A computer measures how these signals interact with brain cells and translates these signals into a detailed image of the brain
Used to study the structures of the brain as well as to identify tumours or types of brain damage

20. Did You Know...
A magnetic resonance imaging (MRI) is an imaging test that uses powerful magnetic forces and radio-frequency (RF) waves to make detailed 3-dimensional pictures of organs, soft tissues, bone and most other internal body structures. Some MRI scans require a contrast medium to provide clearer images.
Different tissues react differently to the magnetic current and this produces various images. No ionizing radiation is used in MRI.
MRI cannot be done if the person has certain metal devices inside their body (such as a pacemaker, implanted port or pump). The magnetic force is so strong that it can damage or dislodge these devices. In most cases, MRI can be done on people who have joint replacements, surgical clips or screws.

21. fMRI (type of MRI scan) Means functional magnetic resonance imaging
Can directly observe both the functions of different structures of the brain and which structures participate in specific functions by recording the movement of blood flow

23. To Summarize...
How Does an MRI Work? (1:21) ?v=1CGzk- nV06g&list=PL1872FCF16467E 980
How Does a PET Scan Work? (1:33) ?v=GHLBcCv4rqk&feature=c4- overview- vl&list=PL1872FCF16467E980
How CT Scan Machine Works (1:01) ?v=tqGmqRrxajQ