BRAIN RESEARCH METHODS

1. BRAIN RESEARCH METHODS AMY COOPER

2. GLOSSARY • PG 1 – Direct Brain Stimulation • PG 2 – Electrode Stimulation • PG 3 – Direct Brain Stimulation • PG 4 – Transcranial Magnetic • Stimulation (TMS) • PG 5 – Procedure of TMS • PG 6 – Pros and Cons of TMS • PG 7 – Electroencephalography • (EEG) • PG 8 – Procedure of EEG • PG 9 – Pros and Cons of EEG • PG 10 – Computerised • Tomography (CT) • PG 11 – Procedure of CT • PG 12 – Pros and Cons of CT • PG 13 – Magnetic Resonance • Imaging (MRI) • PG 14 – Procedure of MRI PG 15 – Pros and Cons of MRI PG 16 – Positron Emission Tomography (PET) PG 17 – Procedure of PET PG 18 – Pros and Cons of PET PG 19 – Single Photon Emission Computed Tomography (SPECT) PG 20 – Procedure of SPECT PG 21 – Pros and Cons of SPECT PG 22 – Functional Magnetic Resonance Imaging (fMRI) PG 23 – Pros and Cons of fMRI

3. DIRECT BRAIN STIMULATION Using device that emits a weak electric current to activate/disrupt the normal activity of neurons in specific brain area’s Can be done by using electrode or pulses of transcranial magnetic stimulation Direct stimulation of a specific brain area controls/involved with response and may also disrupt functioning of the specific area, thereby impairing the response. Disruptive effect only apparent when person is actively engaged in the behaviour being disrupted/impaired Disruptive effect most evident in complex functions such as language and memory

4. ELECTRODE STIMULATION • Wilder Penfield in 1940’s to 1960’s used technique to locate and identify area’s of the cerebral cortex responsible for different functions – producing a ‘map’ of the cortex to treat epilepsy. Treatment involved surgically removing area of cortex that’s the source of the epileptic seizures as a last resort for patients. When stimulated area of the cortex Penfield ask patients to report their experiences Electrode is a small, electrified fine wire which is inserted into/placed onto a specific area of the brain Electrode used to deliver a precisely regulated electric current to the brain area stimulating a specific brain area STIMULATION OF: Occipital Lobe – patients reported seeing flickering lights, spots and colours Auditory Cortex – ‘hearing’ doorbells, car engines Somatosensory Cortex – ‘feeling’ a tingling sensation in various parts of the body Primary Motor Cortex – patients responded by moving specific body parts Electrodes also used for therapeutic purposes in a procedure involving deep brain stimulation ie. Stimulation served to reduce activity in area believed to over activate depression – patients almost immediately after reported mental experiences such as a sense of ‘connectedness’

5. TRANSCRANIAL MAGNETIC STIMULATION (TMS) • The magnetic field includes a harmless electric current in time-varying charges • Can be used for mapping brain areas, pinpoint/diagnose brain damage and to track patients recovery ie. From a stroke • Repetitive TMS (rTMS) used in procedures involving repeated (not necessarily rapid) delivery of a pulse causing area of brain to be inactive without unwanted side effects – used to study brain organisation, treating serious cases of depression and is capable of changing the activity in brain area TMS is a direct brain-stimulation technique that delivers a magnetic field through the scull and temporarily activates/disrupts normal activity of neurons in specific areas of the cerebral cortex TMS only stimulates part of brain that lies 2-3 cm into brain directly beneath coil. Researchers can use TMS to study functions of specific areas of the cerebral cortex CEREBRAL CORTEXT ACTIVATION FOR A SHORT PERIOD The magnetic field pulse is transmitted from a small copper electromagnetic coil that is enclosed in plastic and placed next to scalp. An electric current is sent through the coil, which induces a magnetic field around the coil and creates the pulse. The single pules is then directed through the skin and scalp to underlying clusters of neurons; activating the neurons and they send a burst if neural impulses (electrical activity) to adjacent neurons, activating them – brief single pulse can cause a burst in brain activity

6. PROCEDURE OF TRANSCRANIAL MAGNETIC STIMULATION (TMS) PRIOR TO THE TREATMENT The psychiatrist will first give the patient a motor threshold test (determining the magnetic field strength required to cause movement in patients thumb). This test determines the magnetic field strength that will be used in the patient’s treatment. After the motor threshold test, the doctor will then determine where to place the treatment coil on patients head to provide the best treatment DURING THE TREATMENT During the TMS procedure, the patient will sit in a chair, awake and alert during the entire treatment. They will then wear earplugs because of a tapping sound made by the machine AFTER THE TREATMENT During the treatment some patients may feel mild to moderate scalp discomfort, which can be eased with any pain relief medication (ie Aspirin) Patient can return to your normal activity (ie driving) immediately after the procedure

7. TRANSCRANIAL MAGNETIC STIMULATION (TMS) ADVANTAGES LIMITAIONS Extremely invasive procedure, imposes risk’s that, by todays ethical standards would be considered unacceptable Involves difficulty in generalising results Can’t be used on individuals who have any metal implanted/metal devises in their body or have a history of seizures rTMS cause scalp pain/headaches in 30% of patients Magnetic field only affects brain that lies immediately bellow scull • Effective and reliable technique of brain research • Non-invasive procedure • No substances are consumed • No sedation or anaesthetic administered • Results of patients are generally consistent • Patient awake and alert while receiving stimulation • No use of X-rays/radioactive substances • Researches can manipulate a damaged brain to measure effects instead of relying of case studies

8. ELECTROENCEPHALOGRAPHY (EEG) Assist’s with study of various brain-related medical conditions - brain damage, neurological disorders such as epilepsy and Parkinson’s disease. EEG’s also identity distinctive patterns of electrical activity in the brain often occurring in people with depression, schizophrenia. Direct stimulation of a specific brain area controls/involved with response and may also disrupt functioning of the specific area, thereby impairing the response. Disruptive effect only apparent when person is actively engaged in the behaviour being disrupted/impaired Disruptive effect most evident in complex functions such as language and memory

9. PROCEDURE OF ELECTROENCEPHALOGRAPHY (EEG) PRIOR TO THE TREATMENT Before the EEG, the patient lays down on the examining table/bed whilst their scalp is cleaned to remove any dirt or dead skin in order to ensure clear detection of the brains electrical activity. Then the electrodes are attached to their scalp DURING THE TREATMENT During an EEG, the electrical signals of the brain are recorded. This electrical activity is detected by electrodes placed on the patient's scalp and transmitted to a polygraph that records the activity. Electrical signals produced by the brain neurons are picked up by the electrodes and transmitted to a polygraph, where they produce graphs on moving paper using an ink on a computer screen. The patient may be asked various things such as to relax and lie first with your eyes open, lay with their eyes closed, to stare at a flashing light or to breathe deeply and rapidly. All of these activities create changes in the brain-wave patterns. An EEG can also be performed in a course of night whilst the patient is asleep for recording a sleep disorder AFTER THE TREATMENT After the EEG is performed, the electrodes are removed and the glue that held them in place is washed off with acetone. The patient is able to go back to normal activities immediately after and may drive home

10. ELECTROENCEPHALOGRAPHY (EEG) ANDVANTAGES LIMITAIONS • Relatively cheap • Fast • Safe • Non invasive procedure • Doesn’t cause pain • Doesn’t provide detailed information about which particular structures of the brain are activated/what their specific functions may be • Difficult to pinpoint specific area that’s the source of brain wave activity • Strength of electrical activity reduced as a result of needing to travel through thick brain structure of the skull • EEG merely provides a summary of all the activity of neurons firing within the brain

11. COMPUTERISED TOMOGRAPHY (CT) CT is a neuroimaging technique that produces a computer-enhanced image of a cross-section of the brain from X-rays taken from different angles Can only be performed by a doctor called a radiologist. CT rarely has any serious side affects. CT scanning provides a new way of looking at a live intact human brain without using invasive and dangerous procedures. The X-ray procedure of a CT is believed to be harmless. http://www.youtube.com/watch?v=dHBUNoMMj6w • USE CT FOR: • Spotting and identifying the precise location and extent of damage to/abnormities in various brain structures/areas • Research in identifying specific abnormalities in people with mental illnesses

12. PROCEDURE OF COMPUTERISED TOMOGRAPHY (CT) DURING THE TREATMENT Patient must lie extremely still on the scanner bed with their head inserted into the scanner opening. An X-ray source slowly moves circularly around patients head. An X-ray detector opposite the X-ray receives the information; creating thin, horizontal cross-sectional image of the brain PRIOR TO THE TREATMENT The patient must first be given an injection of iodine in hand/arm directly into blood stream – used to highlight the brain’s blood vessels. AFTER THE TREATMENT The computer combines all the cross-sectional images of the brain creating a 2/3 dimensional image of the brain called a computerised tomogram scan (CT scan)

13. COMPUTERISED TOMOGRAPHY (CT) ADVANTAGES DISADVANTAGES • Non-invasive procedure • No serious side effects • Doesn’t provide information about activity (function) of brain, only its structure

14. MAGNETIC RESONANCE IMAGING (MRI) The vibrations are detected by a huge magnet in the chamber surrounding the motionless person, and are channelled into a computer. The computer than processes the vibrations and assembles them into a coloured image that indicates areas of high and low brain activity. MRI can detect and display extremely small changes in the brain MRI is a neuroimaging technique that uses harmless magnetic fields and radio waves to vibrate atoms in the brain’s neurons to produce an image of the brain • MRI measures the vibration of atoms in neurons, it detects if neurons are firing during particular activities; if atoms are vibrating that means the neurons are firing. Can be used to diagnose unusual disorders such as Prosopagnosia and Akinetopsia

15. PROCEDURE OF MAGNETIC RESONANCE IMAGING (MRI) PRIOR TO THE TREATMENT The patient is directed to a special self-contained room where the MRI machine is located. The patient will then be asked to lie down on a cushioned table, where a device will be placed around their head. Then they will be moved into the magnet. The technologist will leave the room but will stay in constant contact with the patient throughout the entire exam. DURING THE TREATMENT When the MRI scan begins, the patient will hear a muffled thumping sound that will last for several minutes, while the pictures are being taken. Earplugs or music will be provided so that the noise doesn't sound so loud. The patient must lie as still as possible during the procedure as any movement during this time will blur the picture. AFTER THE TREATMENT After the scanning is complete (generally about 30 minutes) the technologist will return to help the patient off the table and then they may go home and assume regular activity

16. MAGNETIC RESONANCE IMAGING (MRI) ADVANTAGES LIMITATIONS • Enables even more precision in the study of structure of the live human brain • Non-invasive • Harmless • Provides more detailed and clearer images of brain, which are almost of photographic quality • Doesn’t use X-rays or radioactive substances • Clearer, more detailed images than a CT • It cannot be used with people who have internal metallic devices such as heart pacemakers or steel pins in bones • Like CT its main limitation fro brain study is that it shows only brain structure/anatomy and not function

17. POSITRON EMISSION TOMOGRAPHY (PET) PET is a neuroimaging technique that uses a radioactive tracer to enable production of a computer generated image that provides information about brain structure, activity and function during various tasks Shows structure and function of brain when asked certain questions ie. Count backwards from 10. This shows the brains activity and identifies what each part of the brains function is • Dye doesn’t last long • High quality images http://www.youtube.com/watch?v=d9iOxMFmPlA

18. PROCEDURE OF POSITRON EMISSION TOMOGRAPHY (PET) PRIOR TO THE TREATMENT Patients shouldn’t eat six hours leading up to the scan and will be encouraged to drink a lot of water. The patient is taken into an injection room, where the radioactive dye is administered as an intravenous injection. It will take around 60 minutes for the substance to travel through your body and accumulate in the tissue under study. DURING THE TREATMENT During the PET procedure, the patient will lay on a bed which slides into the machine. The patient must lye as still as possible for the scan to be clear

19. POSITRON EMISSION TOMOGRAPHY (PET) ADVANTAGES DISADVANTAGES • Enables detailed images of the functioning brain; that is a brain as its performing tasks • People without brain damage can be used in research studies • Colour coding of PET scans makes it relatively simple to identify area of the brain that are active and inactive • Researcher cannot determine whether an active brain area is actually involved in mental processes or behaviour under investigation • PET doesn’t necessarily pick up the very rapid progression/changes in brain activity because it needs a 40 second interval between scans, each of which go for 30 seconds

20. SINGLE PHOTON EMISSION COMPUTED TOMOGRAPHY (SPECT) SPECT uses longer-lasting radioactive tracer and a scanner to record data that a computer uses to construct two/three dimensional images of active brain regions • Brain disorders – including stroke, seizure and Alzheimer’s disease • Heart problems – including chest pain, heart attack and arterial blockages in the heart • Various forms of cancer – such as primary tumours and those that have spread to other parts of the body (metastasized) Detects Oxygen in brain. More O the more activity in that brain region. Used for longer lasting tasks ie. Counting backwards from 100 2

21. PROCEDURE OF SINGLE PHOTON EMISSION COMPUTED TOMOGRAPHY (SPECT) PRIOR TO THE TREATMENT The radioactive substance will be administered to you through an injection or an intravenous (IV) infusion into one of the veins in your arm. Prior to the scan, you may have to lie down quietly in a room for around 15 minutes or more to allow proper absorption of the radioactive substance DURING THE TREATMENT The health care team members will position the patient on a table in the room where your SPECT scan test is to be conducted. A large circular device, a SPECT machine has a special camera known as a gamma camera that measures the amount of radioactive substance absorbed by the patient’s body. The SPECT machine will rotate around the patient during the scan while the patient is lying on the table. It then shoots pictures of organs and other internal structures in the patient’s brain. The pictures are then processed by a computer to generate 3-D images of the body AFTER THE TREATMENT In just a few hours after the SPECT scan, most of the radioactive substance is flushed out by the body through the urine

22. SINGLE PHOTON EMISSION COMPUTED TOMOGRAPHY (SPET) PROS CONS • Can be combined with CT scanning for better results • Non-invasive • Longer lasting • SPECT images not a good quality as PET • Lower resolution images therefore not as clear or detailed

23. FUNCTIONAL MAGNETIC RESONANCE IMAGING (fMRI) fMRI is a neuroimaging technique that enables the identification of the brain areas that are particularly active during a given task by detecting changes in oxygen levels in the blood flowing trough the brain • MRI measures oxygen levels in certain areas of the brain to determine what parts of the brain are being used and what neural pathways are being used

24. FUNCTIONAL MAGNETIC RESONANCE IMAGING (fMRI) PROS CONS • Doesn’t use radiation • Virtually no risks • Easy to use • High resolution images • Expensive • fMRI can only look at blood flow in the brain. It can't home in on the activities of individual nerve cells (neurons), which are critical to mental function • can be difficult to interpret