Neuroimaging in Understanding Brain Disorders

“The brain is more than an assemblage of autonomous modules, each crucial for a specific cognitive function. Every one of these functionally specialized brain regions must interact with dozens or hundreds of others, their total integration creating something like a vastly complicated orchestra with thousands of instruments, an orchestra that conducts itself, with an ever-changing score and repertoire.”

For most of us, we have always been stranded by the question: Can we truly understand our brain? And if we can, then how? Over the last 100 years, neuroscience has made quite much progress. We have learned that there are neurons in the brain, we have learned a lot about the psychological aspect of the brain, also known as the mind, but connecting those two worlds, understanding how these computational circuits in the brain work in coordinated fashion are generating decisions and thoughts and feelings and sensations, that link remains very elusive. We have learned about the many disorders like Epilepsy¹ or Alzheimer’s² but finding an antidote to the misery they cause, both physically and mentally, is still a tough row to hoe. Hence, the journey begins to understand, study, and analyse the process of the brain functions.

The brain researchers, mind-boggled bogglers, called Neuroscientists, devised a discipline referred to as Neuroimaging (also known as brain scanning). It includes using various techniques to either directly or indirectly image the brain’s structure, function, and pharmacology³. Physicians who specialize in the performance and interpretation of neuroimaging in the clinical setting are known as neuroradiologists.

The brain researchers, mind-boggled bogglers, called Neuroscientists, devised a discipline referred to as Neuroimaging (also known as brain scanning). It includes using various techniques to either directly or indirectly image the brain’s structure, function, and pharmacology³. Physicians who specialize in the performance and interpretation of neuroimaging in the clinical setting are known as neuroradiologists.

Structural imaging deals with the structure of the brain and the diagnosis of large-scale intracranial⁴ disease (such as tumours), as well as traumatic head injury, whereas Functional imaging (which is much more interesting) is used to diagnose metabolic diseases⁵ and lesions⁶ on a finer scale, significantly contributing towards the neurological and cognitive-psychology approach. The pre-eminent part of it allows the brain’s information processing to be visualized directly because activity in the involved brain regions increases metabolism and “lights up” in the scan.

Unlike the early days when boring holes inside the skull, possibly to alleviate the brain disorders was a trend, development in technological advances has led us to neuroimaging techniques such as MRIs or CT scans. What do they stand for? What are they about? How do physicians conduct the- stop, hold your breath, stay patient, you will get to know it all!

The four most common brain imaging techniques are EEG, PET, MRI, and CT.

Electroencephalography (EEG)

This technique is used to demonstrate brain activity in certain psychological states, such as alertness or drowsiness. It is particularly used to diagnose conditions such as brain tumours, sleep disorders, seizures, inflammation of the brain (encephalitis), brain dysfunction due to many causes (encephalopathy), and many more.

It is a test which involves recording of  the brain’s electrical signals by using small metal discs (called electrodes) that are attached to your scalp. The brain activity shows up on an EEG recording as wavy lines. Hence, it is a snapshot of the electrical activity of your brain in the temporal scale.  

Positron Transmission Tomography (PET)

These scans measure the sugar glucose level in the brain to illustrate neural firing⁷. This works because the active nerve cells use glucose as fuel. The test uses a safe injectable radioactive chemical called a radiotracer and a PET scanner device. The scanner detects diseased cells that absorb large amounts of the radiotracer, indicating a potential health problem.

When parts of the brain become active, blood (which contains the tracer) is sent to deliver the oxygen. This creates visible spots, which are then picked up by the detectors and used to create a video image of the brain while performing a particular task.

Also, it is used to check for signs of cancers, coronary⁸ heart diseases, dementia⁹, Alzheimer’s disease, etc.

Magnetic Resonance Imaging (MRI)

This test uses powerful magnets, radio waves, and a computer to make detailed pictures of the inside of your body. They are the most useful to the field of psychology. For example, an MRI helps a doctor diagnose a disease or injury, and it can monitor how well you are doing with treatment.

MRIs can be done on different parts of your body:

• MRI of the brain helps find blood vessel damage (including aneurysm¹⁰), stroke, multiple sclerosis¹¹, inner ear problems, etc.
• MRI of the heart or blood vessels looks for blocked blood vessels, pericarditis¹², problems with the aorta, etc.
• MRI of the bones and joints look for arthritis¹³, bone infections, problems in the spine, damage to joints, etc.

For example, when a person processes visual information, blood rushes to the back of the brain, which is where the occipital lobe¹⁴ is located. fMRI makes it possible to show when things happen, how brain areas change with experience, and which brain areas work together. They have been used to study a wide range of psychological phenomena, including (but not limited to) the neural activity of telling a lie especially in criminal cases, the differences between novices and experts when playing a musical instrument, and what happens inside our heads when we dream.

Computed Tomography (CT or CAT)

This scan uses computers and rotating X-ray machines to create cross-sectional body images. These images provide more detailed information than standard X-ray images. They use a narrow X-ray beam that circles one part of your body, providing a series of images from many different angles. Like one piece in a loaf of bread, this two-dimensional (2D) scan shows a “slice” of the inside of your body.

This process is repeated to produce several slices. The computer stacks these scans one on top of the other to create a detailed image of your organs, bones, or blood vessels. For example, a surgeon may use this scan to look at all sides of a tumor to prepare for an operation.

CT scans can be used to locate a tumour, blood clot, excess fluid, or infection. Moreover, doctors use them to guide treatment plans and procedures such as biopsies¹⁵, surgeries, and radiation therapy.

Concludingly, the ability to measure and recreate brain activity at the level of specific neurons at will is about to transform us in ways that no other invention ever has. The invention of fire, of the wheel, of antibiotics or the Internet changed how we live our lives in profound ways. It made our lives safer, more comfortable, and more exciting. However, they have not changed who we are. Being able to record and manipulate brain activity will change who we are. It will serve as an interface through which computers can become part of our brain (artificially), and through which our brains could directly interface with each other.

Glossary:

1. Epilepsy: A disorder in which the nerve cell activity in the brain is disturbed, causing seizures.
2. Alzheimer’s disease: A progressive disease that destroys memory and other important mental functions.
3. Pharmacology: It is the study of drugs and their actions on living systems.
4. Intracranial: Inside of the skull.
5. Metabolic disease: Any type of disease that disrupts the normal biochemical functioning of your body.
6. Lesions: An abnormal area of tissue inside or outside the body that may get bigger or change appearance.
7. Neural firing: Interaction between the neurons.
8. Coronary: Relating to the blood vessels.
9. Dementia: Impaired ability to remember, think or make decisions that interfere with doing everyday activities.
10.  Aneurysm: Weakening of the artery (blood vessel) that creates a bulge.
11. Multiple sclerosis: A disease in which the immune system eats up the protective covering of the nerves.
12.  Pericarditis: A swelling and irritation of the thin, sac-like membrane surrounding the heart (pericardium).
13.  Arthritis: Inflammation of one or more joints, causing pain and stiffness that worsen the age.
14.  Occipital lobe: Part of the human brain responsible for interpreting the information from the eyes and turning it into the world as a person sees it.
15.  Biopsies: involve the removal of the tissues from any part of the body to examine it for any disease.

Reviewer: Areeba Aziz

Editor: Dr. Pradeep Kumar Mishra