Tools We Use to Study the Brain

CAT scan (computer axial tomography):

A CAT scanner emits a series of narrow beams through the human body as it moves through an arc. Inside the CAT scanner there is an X-ray detector which can see hundreds of different levels of density. This data is transmitted to a computer, which builds up a 3-D cross-sectional picture of the part of the body and displays it on the screen. 

Structural MRI (Magnetic Resonance Image):

An MRI scan is a radiology technique that uses magnetism, radio waves, and a computer to produce images of body structures. The image and resolution produced by MRI is quite detailed and can detect tiny changes of structures within the body. For some procedures, contrast agents, such as gadolinium, are used to increase the accuracy of the images.



 

 Diffusion-Tensor MRI (DTI):

 Diffusion Tensor Magnetic Resonance Imaging, or DT-MRI, is a technology that measures the random motion of hydrogen atoms within water molecules in all three dimensions, non-invasively, and in vivo. DT-MRI adds to conventional MRI the capability of measuring the random motion of water molecules, referred to as diffusion.

EEG (electroencephalograph):

An EEG is a test to measure the electrical activity of the brain. An EEG measures impulses in the brain. Flat metal disks called electrodes are placed all over your scalp. The disks are held in place with a sticky paste. The electrodes are connected by wires to a speaker and recording machine.
The recording machine changes the electrical signals into patterns that can be seen on a computer. It looks like wavy lines and this data can help diagnose seizures or other illnesses.

 

PET scan (Positron emission tomography):

A PET scan is an imaging test that uses a radioactive substance called a tracer to look for disease in the body. A PET scan uses a small amount of radioactive material (tracer). The  tracer is given through a vein (IV), most often on the inside of your elbow. The tracer travels through your blood and collects in organs and tissues. This helps the radiologist see certain areas of concern more clearly. How long the test takes depends on what part of the body is being scanned.

fMRI (functional MRI):

fMRI is based on the same technology as magnetic resonance imaging (MRI) -- a noninvasive test that uses a strong magnetic field and radio waves to create detailed images of the body. But instead of creating images of organs and tissues like MRI, fMRI looks at bloodflow in the brain to detect areas of activity. These changes in blood flow, which are captured on a computer, help doctors understand more about how the brain works.

phMRI (pharamacological MRI):
the use of fMRI to map spatiotemporal patterns of brain activity induced by pharmacological agents, has provided a robust and flexible tool to resolve brain circuits and mechanism-specific functional changes produced by selective intervention in different neurotransmitter systems in vivo. 

TMS (transcranial magnetic stimulation):
TMS uses a magnet instead of an electrical current to activate the brain. An electromagnetic coil is held against the forehead and short electromagnetic pulses are administered through the coil. The magnetic pulse easily passes through the skull, and causes small electrical currents that stimulate nerve cells in the targeted brain region. And because this type of pulse generally does not reach further than two inches into the brain, scientists can select which parts of the brain will be affected and which will not be. The magnetic field is about the same strength as that of a magnetic resonance imaging (MRI) scan. 

Sources:

Source 1
Source 2
Source 3

Source 4 

Source 5 
Source 6
Source 7
Source 8

Deafness: An Inside Look

Sound waves enter the ear, go down the ear canal (auditory), and hit the eardrum, which vibrates. The vibrations from the eardrum pass to the three ossicles (bones called the malleus (hammer), incus (anvil) and stapes) in the middle ear. These occicles amplify the vibrations, which are then picked up by small hair-like cells in the cochlea; they move as the vibrations hit them, the movement data is sent through the auditory never to the brain. The brain processes the data, which we interpret as sound.

A patient with mild hearing impairment may have problems understanding speech, especially if there is a lot of noise around, while those with moderate deafness may need a hearing aid. Some people are severely deaf and depend on lip-reading when communicating with others. People who are profoundly deaf can hear nothing at all. In order to communicate spontaneously and rapidly with people, they are totally reliant on lip-reading and/or sign language. People who are born deaf find lip-reading much harder to learn compared to those who became hearing impaired after their had learned to communicate orally (with sounds).

Deafness can be an impairment one is born with, caused themselves, happened while going through another illness like chicken pox or AIDS, or occurred after a severe accident. Whatever the reason, treatment depends on the severity of the hearing impairment. Hearing loss is when one can still hear, but the quality is diminished while deafness is when the sound is completely diminished no matter how amplified a sound may be. Sensorineural hearing loss is incurable. When the hair cells in the cochlea are damaged, they cannot be repaired. However, various treatments and strategies can help improve the patient's quality of life. Hearing aids are the most common treatments because while they do not cure deafness, they help amplify the sound so that there is a little bit of hearing.

Sources:
Source 1
Source 2

Alzheimer's: Forget Me Not

If you ever watched The Notebook and witnessed one of the protagonists change drastically in the end, you have an idea what Alzheimer's can look like. Alzheimer's is a general term for memory loss and other intellectual abilities serious enough to interfere with daily life. Alzheimer's disease accounts for 50 to 80 percent of dementia cases. While it is common for elderly people to suffer from this disease, there is a 5% of people aged 40-50 that suffer from Alzheimer's. Alzheimer's is a progressive disease, where dementia symptoms gradually worsen over a number of years. In its early stages, memory loss is mild, but with late-stage Alzheimer's, individuals lose the ability to carry on a conversation and respond to their environment.

Like all types of dementia, Alzheimer's is caused by brain cell death. It is a neurodegenerative disease, which means there is progressive brain cell death that happens over a course of time. The total brain size shrinks with Alzheimer's - the tissue has progressively fewer nerve cells and connections. While they cannot be seen or tested in the living brain affected by Alzheimer's disease, postmortem/autopsy will always show tiny inclusions in the nerve tissue, called plaques and tangles. Plaques are found between the dying cells in the brain - from the build-up of a protein called beta-amyloid (you may hear the term "amyloid plaques"). The tangles are within the brain neurons - from a disintegration of another protein, called tau.

Currently, there is no cure for Alzheimer's. But drug and non-drug treatments may help with both cognitive and behavioral symptoms. The U.S currently only allows cholinesterase inhibitors (Aricept, Exelon, Razadyne, Cognex) and memantine (Namenda) to treat the cognitive symptoms (memory loss, confusion, and problems with thinking and reasoning) of Alzheimer's disease. While current medications cannot stop the damage Alzheimer’s causes to brain cells, they may help lessen or stabilize symptoms for a limited time by affecting certain chemicals involved in carrying messages among the brain's nerve cells.Some doctors also prescribe high doses of vitamin E for cognitive changes of Alzheimer's disease. Change can be stressful for anyone and can be especially difficult for a person with Alzheimer's disease. It can increase the fear and fatigue of trying to make sense out of an increasingly confusing world. Identifying what has triggered a behavior can often help in selecting the best approach to deal with it.


We've been told that there's little we can do to prevent Alzheimer’s disease and other types of dementia but hope for the best and wait for a pharmaceutical cure. But the truth is you can reduce your risk by eating right, exercising, staying mentally and socially active, and keeping stress in check. By leading a brain-healthy lifestyle, you may be able to prevent Alzheimer’s symptoms and slow down, or even reverse, the process of deterioration.




Sources:
Source 1
Source 2
Source 3
Source 4
Source 5
Source 6

What An Audiologist Does

Audiologists are the primary health-care professionals who evaluate, diagnose, treat, and manage hearing loss and balance disorders in adults and children. They prescribe, fit, and dispense hearing aids and other amplification and hearing assistance technologies.Audiologists assess and treat individuals, especially children, with central auditory processing disorders and also patients with tinnitus (noise in the ear, such as ringing.  Audiologists are trained to carry out detailed assessments by performing a number of specialized auditory (hearing) and vestibular (balance) tests. Audiologists dispense and fit hearing aids, administer tests of balance to evaluate dizziness, and provide hearing rehabilitation training. Audiologists refer patients to physicians when the hearing problem needs medical or surgical evaluation.


Generally, to practice as an audiologist, you will need to earn a Doctor of Audiology degree or AuD. This usually takes four years after first earning a bachelor's degree. Most programs suggest that a candidate's undergraduate education should consist of a strong arts and sciences focus with course work in linguistics, phonetics, psychology, speech and hearing, mathematics, biological sciences, physical sciences and social science. Licensure is also required in the US and cannot be done without graduating from an accredited school.

In 2012, audiologists earned an average yearly salary of $69,720 and median hourly wages of $33.52 (US).


Sources:
Source 1
Source 2
Source 3
Source 4