Huntington’s disease (HD) is a neurodegenerative genetic disorder that affects muscle coordination and leads to cognitive decline and psychiatric problems. It typically becomes noticeable in mid-adult life. HD is the most common genetic cause of abnormal involuntary writhing movements called chorea, which is why the disease used to be called Huntington’s chorea. The disease is caused by an autosomal dominant mutation in either of an individual’s two copies of a gene called Huntingtin, which means any child of an affected person typically has a 50% chance of inheriting the disease. Physical symptoms of Huntington’s disease can begin at any age from infancy to old age, but usually begin between 35 and 44 years of age.
MRI is the investigative tool of choice for neurological cancers as it is more sensitive than CT for small tumors and offers better visualization of the posterior fossa. The contrast provided between grey and white matter make it the optimal choice for many conditions of the central nervous system including demyelinating diseases, dementia, cerebrovascular disease, infectious diseases and epilepsy.
Image: MRI image of white matter tracts.
Hydrocephalus is a medical condition in which there is an abnormal accumulation of cerebrospinal fluid (CSF) in the ventricles, or cavities, of the brain. This may cause increased intracranial pressure inside the skull and progressive enlargement of the head, convulsion, tunnel vision, and mental disability. Hydrocephalus can also cause death. Although it does occur in older adults, it is more common in infants.
Image: Hydrocephalus seen on a CT scan of the brain
Chiari malformation is a malformation of the brain. It consists of a downward displacement of the cerebellar tonsils through the foramen magnum (the opening at the base of the skull), sometimes causing non-communicating hydrocephalus as a result of obstruction of cerebrospinal fluid (CSF) outflow. The cerebrospinal fluid outflow is caused by phase difference in outflow and influx of blood in the vasculature of the brain. It can cause headaches, fatigue, muscle weakness in the head and face, difficulty swallowing, dizziness, nausea, impaired coordination, and, in severe cases, paralysis.
Image: A T1-weighted sagittal MRI scan, from a patient with an Arnold-Chiari malformation, demonstrating tonsillar herniation of 7mm
Arachnoid cysts are cerebrospinal fluid covered by arachnoidal cells and collagen that may develop between the surface of the brain and the cranial base or on the arachnoid membrane, one of the three membranes that cover the brain and the spinal cord. Arachnoid cysts are a congenital disorder, and most cases begin during infancy; however, onset may be delayed until adolescence.
Image: An MRI of a 25 year old woman with left frontotemporal arachnoid cyst.
The ependyma is made up of ependymal cells, ependymocytes. These epithelial-like cells line the CSF-filled ventricles in the brain and the central canal of the spinal cord. The cells are ciliated simple cuboidal epithelium-like cells. Their apical surfaces are covered in a layer of cilia, which circulate CSF around the CNS. Their apical surfaces are also covered with microvilli, which absorb CSF. Ependymal cells are a type of glial cell and are also CSF producing cells. Within the ventricles of the brain, a population of modified ependymal cells and capillaries together form a system called the choroid plexus, which produces the CSF.
Modified tight junctions between ependymal cells control fluid release across the epithelium. This release allows free exchange between CSF and nervous tissue of brain and spinal cord. This is why sampling of CSF (e.g. through a “spinal tap”) gives one a window to the CNS.
Image: Photomicrograph of hematoxylin stained section of normal ependymal cells at 400x magnification.
Dandy–Walker syndrome (DWS), is a congenital brain malformation involving the cerebellum and the fluid filled spaces around it. A key feature of this syndrome is the partial or even complete absence of the part of the brain located between the two cerebellar hemispheres (cerebellar vermis). The Dandy–Walker complex is a genetically sporadic disorder that occurs one in every 30,000 live births. Prenatal diagnosis and prognosis of outcomes associated with Dandy-Walker can be difficult.
The term Dandy–Walker represents not a single entity, but several abnormalities of brain development which coexist. There are, at present, three identified types of Dandy–Walker complexes. These represent closely associated forms of the disorder: DWS malformation, DWS mega cisterna magna and DWS variant.
Image: Variant DWS with dysplasia of the pons and cerebellum in a 8-year old. T2 weighted sagittal MRI.
More than a decade of research on children raised in institutions shows that “neglect is awful for the brain,” says Charles Nelson, a professor of pediatrics at Harvard Medical School and Boston Children’s Hospital. Without someone who is a reliable source of attention, affection and stimulation, he says, “the wiring of the brain goes awry.” The result can be long-term mental and emotional problems.
A lot of what scientists know about parental bonding and the brain comes from studies of children who spent time in Romanian orphanages during the 1980s and 1990s. Children likeIzidor Ruckel, who wrote a book about his experiences.
When Ruckel was 6 months old, he got polio. His parents left him at a hospital and never returned. And Ruckel ended up in an institution for “irrecoverable” children.
But Ruckel was luckier than many Romanian orphans. A worker at the orphanage “cared for me as if she was my mother,” he says. “She was probably the most loving, the most kindest person I had ever met.”
Then, when Ruckel was 5 or 6, his surrogate mother was electrocuted trying to heat bath water for the children in her care. Ruckel ended up in an institution for “irrecoverable” children, a place where beatings, neglect, and boredom were the norm.
Researchers began studying the children in Romanian orphanages after the nation’s brutal and repressive government was overthrown in 1989. At the time, there were more than 100,000 children in government institutions. And it soon became clear that many of them had stunted growth and a range of mental and emotional problems.
When Nelson first visited the orphanages in 1999, he saw children in cribs rocking back and forth as if they had autism. He also saw toddlers desperate for attention.
"They’d reach their arms out as though they’re saying to you, ‘Please pick me up,’ " Nelson says. "So you’d pick them up and they’d hug you. But then they’d push you away and they’d want to get down. And then the minute they got down they’d want to be picked up again. It’s a very disorganized way of interacting with somebody."
The odd behaviors, delayed language and a range of other symptoms suggested problems with brain development, Nelson says. So he and other researchers began studying the children using a technology known as electroencephalography (EEG), which measures electrical activity in the brain.
Many of the orphans had disturbingly low levels of brain activity. “Instead of a 100-watt light bulb, it was a 40-watt light bulb,” Nelson says.
As the children grew older, the researchers were able to use MRI to study the anatomy of their brains. And once again, the results were troubling. “We found a dramatic reduction in what’s referred to as gray matter and in white matter,” Nelson says. “In other words, their brains were actually physically smaller.”
The scientists realized the cause wasn’t anything as simple as malnutrition. It was a different kind of deprivation — the lack of a parent, or someone who acted like a parent.
Top photo: Izidor Ruckel, shown here at age 11 with his adoptive father Danny Ruckel in San Diego, Calif., says he found it hard to respond to his adoptive parents’ love. (Barry Gutierrez for NPR)
Middle photo: In the Institute for the Unsalvageable in Sighetu Marmatiei, Romania, shown here in 1992, children were left in cribs for days on end. (Tom Szalay)
Bottom: Izidor Ruckel dons a hat of a style common in his birthplace, Romania. He now lives in Denver. (Barry Gutierrez for NPR)
Trying to introduce the study of the brain to a bunch of students, I said: “If everything we needed to know the brain about a mile … how far have we walked in this mile?” I got answers [like] 3/4 of a mile… half a mile… quarter mile. And I said, “I think about 3 inches.”
When it comes to the nervous system, there are a large number of diseases where the only real sign that there’s something wrong is the outward manifestation of the disease — the person is acting crazy, or they don’t seem to learn very well, or their movements are disordered in some way. But if you look at the brain with most of the techniques we have, there’s nothing to see.
You’ve gotta see the wires — just have to see where they come from, where they go, what they connect with…
National Geographic looks at the wiring of the brain in exquisite 3D renderings of every synapse, exploring how parts of the brain communicate with each other and animate us.
MRI Scan of the Brain
Magnetic resonance imaging (MRI) techniques provide an extremely detailed, 3-D view of a living brain. The technique is critical for identifying abnormalities such as tumors, spotting the warning signs of some brain diseases, and revealing the extent of trauma from strokes.
Source: National Geographic
Magnetic resonance imaging (MRI) of the brain is a safe and painless procedure that uses a magnetic field and radio waves to produce detailed images of the brain and the brain stem. An MRI differs from a CAT scan (also called a CT scan or a computed axial tomography scan) because it does not use radiation.
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. (Some centers have open MRI machines that have larger openings and are helpful for patients with claustrophobia).
During the exam, radio waves manipulate the magnetic position of the atoms of the body, which are picked up by a powerful antenna and sent to a computer. The computer performs millions of calculations, resulting in clear, cross-sectional black and white images of the body. These images can be converted into three-dimensional (3-D) pictures of the scanned area. This helps pinpoint problems in the brain and the brain stem when the scan focuses on those areas. In some cases, MRI can provide clear images of parts of the brain that can’t be seen as well with an X-ray, CAT scan, or ultrasound, making it particularly valuable for diagnosing problems with the pituitary gland and brain stem.
MRI can detect a variety of conditions of the brain such as cysts, tumors, bleeding, swelling, developmental and structural abnormalities, infections, inflammatory conditions, or problems with the blood vessels. It can determine if a shunt is working and detect damage to the brain caused by an injury or a stroke.
As a young neurosurgery resident at UCSF in the late ’90s, Dr. Charles Cobbs developed a hunch about brain tumors. It was a theory that he now concedes “was not based on a lot of scientific things.”
Cobbs had observed that his patients diagnosed with malignant glioma - an aggressive brain cancer that leaves victims with a two-year life expectancy - were mostly older, well-educated and from higher socioeconomic backgrounds.
Their “hyper-hygienic” lifestyles had possibly left their immune systems susceptible to more common viruses, such as the human cytomegalovirus, or CMV, a herpes virus so ubiquitous that it infects 4 of 5 Americans.
During off-hours, and without formal research funding, Cobbs and a lab partner analyzed dozens of brain tumor samples: All of them were riddled with CMV.
In 2002, the doctor published his novel finding in a leading medical journal Cancer Research where it was quickly dismissed by many of his peers.
"I was left with a lot of self doubt," said Cobbs, now 45. "My fear was that we’d done something incorrect. But now, my confidence is growing."
In February, brain cancer researchers at Duke University Medical Center published the first peer-reviewed report that confirmed Cobbs’ discovery, followed by two reports from independent labs at the M.D. Anderson Cancer Center at University of Texas in Houston and the Karolinska Institute in Stockholm, Sweden. And this month, the National Brain Tumor Society is sponsoring a first-of-its-kind gathering in Boston of the world’s top virologists and glioma experts to examine the possible link between CMV and the deadly brain tumors that are diagnosed in 10,000 Americans every year.
"His discovery opens the door and has broad implications in this field," said Dr. Duane Mitchell, a Duke University Medical Center researcher who is conducting vaccine trials based on Cobb’s findings. “And the door has just been opened.”