METHODS OF INVESTIGATING BRAIN

AND LANGUAGE

1. Traditional Methods2. High-Tech Methods

1. Traditional Methods

Post Mortem ExaminationPost Mortem Examination

Brain-Injured People

Brain-Injured People

Electrical stimulation

Electrical stimulation

Used by Broca to examine the brain of patients who faced language disorders

while they are alive.

- Investigating the language use by

brain-injured patients who have

brain operation.

- The patients might need to

remove a part of their brain due to illness or accident.

- Electrical stimulation of the cerebral cortex in patients who are

conscious during the brain operation.

- This method is established by Penfield in the

1950s.

2. High-Tech

Methods

CAT CAT

PETPET MRI and fMRI

MRI and fMRI

ERPsERPs

Computerized Axial Tomography (CAT)• Is a painless test that uses a special X-ray machine to take pictures of a

patient's brain, skull, and sinuses, as well as blood vessels in the head.

• The doughnut-shaped machine circles the head, taking pictures to provide cross-sections of the brain from various angles. These pictures are sent to a computer that records the images. It also can put them together to form three-dimensional images.

• In preparation for a CT scan, patients are often asked to avoid food, especially when contrast material is to be used. Contrast material may be injected intravenously, or administered by mouth or by an enema in order to increase the distinction between various organs or areas of the body. 

• Patients are placed on a movable table, and the table is slipped into the center of a large donut-shaped machine which takes the X-ray images around the body.

• The actual procedure can take from half an hour to an hour and a half. 

Cranial CAT sCAN

http://www.youtube.com/watch?v=Tx-0emi4m8s

A head CAT scan may be done in order to:detect conditions in the brain such as hydrocephalus (too much fluid in the ventricles), swelling, inflammation, bleeding, and signs of injury.gather information about the presence, location, and size of abscesses, cysts, and tumors.locate birth defects in the brain and skull.evaluate the pituitary gland, pineal gland, and sinuses.look at malformed or injured blood vessels in the head.find the cause of headaches, weakness, or a change in mental status.

Positron Emission Tomography (PET)• An imaging technique which uses small amounts of radio labeled

biologically active compounds (tracers) to help in the diagnosis of disease.

• The tracers are introduced into the body, by either injection or inhalation of a gas, and a PET scanner is used to produce an image showing the distribution of the tracer in the body using the PET scanner —a doughnut-like shaped machine.

• This machine detects and records the energy given off by the tracer substance and, with the aid of a computer, this energy is converted into three-dimensional pictures. 

• The actual procedure can take an hour and a half

PET and PET/CT scans are performed to: detect cancer. determine whether a cancer has spread in the body. assess the effectiveness of a treatment plan, such as cancer therapy. determine if a cancer has returned after treatment. evaluate brain abnormalities, such as tumors, memory disorders and

seizures and other central nervous system disorders. to map normal human brain and heart function.

Image of a typical positron emission tomography

PET scan of the human brain

http://www.youtube.com/watch?v=d9iOxMFmPlA&feature=related

Magnetic resonance imaging (MRI) Types of MRI:

1)Structural MRI (MRI)

2)Functional MRI (FMRI )

Uses a magnetic field and radio waves to produce detailed images of the brain

and the brain stem.

An MRI scanner consists of a large doughnut-shaped magnet that often has a

tunnel in the center. Patients are placed on a table that slides into the tunnel.

MRI is the most frequently used imaging test of the brain and spinal cord. It's

often performed to help diagnose:• Aneurysms • Disorders of the eye and inner ear• Multiple sclerosis• Spinal cord injuries• Stroke• Tumors

fMRI is perform to: examine the anatomy of the brain. determine precisely which part of the brain is handling critical functions

such as thought, speech, movement and sensation, which is called brain mapping

help assess the effects of stroke, trauma or degenerative disease (such as Alzheimer's) on brain function.

monitor the growth and function of brain tumors. guide the planning of surgery, radiation therapy, or other surgical

treatments for the brain.

http://www.youtube.com/watch?v=DZTXa4qerI4&feature=related

Event-related potentialsAn event-related potential (ERP) is the measured brain

response that is the direct result of a specific sensory,

cognitive , or motor event.

ERPs are measured with:

 

1. Electroencephalography (EEG)

2. Magnetoencephalography (MEG)

Electroencephalography (EEG)An electroencephalogram (EEG) is a test used to detect

abnormalities related

to electrical activity of the brain.• An electroencephalogram (EEG) may be done to:• Diagnose epilepsy and see what type of seizures are occurring. EEG is the

most useful and important test in confirming a diagnosis of epilepsy.• Check for problems with loss of consciousness or dementia.• Help find out a person's chance of recovery after a change in consciousness.• Find out if a person who is in a coma is brain-dead.• Study sleep disorders, such as narcolepsy.• Watch brain activity while a person is receiving general anesthesia during

brain surgery.• Help find out if a person has a physical problem (problems in the brain, spinal

cord, or nervous system ) or a mental health problem.

http://www.youtube.com/watch?v=8Q57q_kQPQY&feature=related

Magnetoencephalography (MEG)• Magnetoencephalography (MEG) is a technique for mapping brain

activity by recording magnetic fields produced by electrical currents occurring naturally in the brain, using very sensitive magnetometers.

• Clinically, MEG may be used to detect and localize spiking activity in patients with epilepsy and in localizing brain regions involved in sensory processing and linguistic ability in surgical planning.

• In research, MEG is primarily used in the measurement of time courses of

activity because of its high temporal resolution. MEG enables accurate pinpointing of sources in primary auditory, somatosensory and motor areas.

http://www.youtube.com/watch?v=KoS2UXr0yMg&feature=player_detailpage