Cerebellum and ocular system in the human

In vertebrates, the eyeballs are direct extensions of the brain; that is, they evolved after the brain, and are literally unimpeded access to the cerebellum and cerebrum. Because of this, many ocular tumors or injuries can be far more dangerous to the brain than growths or injuries on any other part of the skull.

Anatome ex omnium veterum recentiorumque observationibus. Thomas Bartholin, 1673.

Ballet dancers’ brains adapt to stop them feeling dizzy

Scientists have discovered differences in the brain structure of ballet dancers that may help them avoid feeling dizzy when they perform pirouettes.

The research suggests that years of training can enable dancers to suppress signals from the balance organs in the inner ear.

The findings, published in the journal Cerebral Cortex, could help to improve treatment for patients with chronic dizziness. Around one in four people experience this condition at some time in their lives.

Normally, the feeling of dizziness stems from the vestibular organs in the inner ear. These fluid-filled chambers sense rotation of the head through tiny hairs that sense the fluid moving. After turning around rapidly, the fluid continues to move, which can make you feel like you’re still spinning.

Ballet dancers can perform multiple pirouettes with little or no feeling of dizziness. The findings show that this feat isn’t just down to spotting, a technique dancers use that involves rapidly moving the head to fix their gaze on the same spot as much as possible.

Researchers at Imperial College London recruited 29 female ballet dancers and, as a comparison group, 20 female rowers whose age and fitness levels matched the dancers’.

The volunteers were spun around in a chair in a dark room. They were asked to turn a handle in time with how quickly they felt like they were still spinning after they had stopped. The researchers also measured eye reflexes triggered by input from the vestibular organs. Later, they examined the participants’ brain structure with MRI scans.

In dancers, both the eye reflexes and their perception of spinning lasted a shorter time than in the rowers.

Dr Barry Seemungal, from the Department of Medicine at Imperial, said: “Dizziness, which is the feeling that we are moving when in fact we are still, is a common problem. I see a lot of patients who have suffered from dizziness for a long time. Ballet dancers seem to be able to train themselves not to get dizzy, so we wondered whether we could use the same principles to help our patients.”

The brain scans revealed differences between the groups in two parts of the brain: an area in the cerebellum where sensory input from the vestibular organs is processed and in the cerebral cortex, which is responsible for the perception of dizziness.

The area in the cerebellum was smaller in dancers. Dr Seemungal thinks this is because dancers would be better off not using their vestibular systems, relying instead on highly co-ordinated pre-programmed movements.

“It’s not useful for a ballet dancer to feel dizzy or off balance. Their brains adapt over years of training to suppress that input. Consequently, the signal going to the brain areas responsible for perception of dizziness in the cerebral cortex is reduced, making dancers resistant to feeling dizzy.

“If we can target that same brain area or monitor it in patients with chronic dizziness, we can begin to understand how to treat them better.”

Another finding in the study may be important for how chronic dizzy patients are tested in the clinic. In the control group, the perception of spinning closely matched the eye reflexes triggered by vestibular signals, but in dancers, the two were uncoupled.

“This shows that the sensation of spinning is separate from the reflexes that make your eyes move back and forth,” Dr Seemungal said. “In many clinics, it’s common to only measure the reflexes, meaning that when these tests come back normal the patient is told that there is nothing wrong. But that’s only half the story. You need to look at tests that assess both reflex and sensation.”

4

Uvulas!

We all know about our uvula - or at least the palatine uvula - the one in our mouths. This hanging mass at the back of our mouth is formed from the soft palate, and is involved in the gag reflex and some languages (but not English). But did you know that we have more uvulas than just that?

Uvula means “little grape"in Latin, and a swollen uvula is called "ūvawhich is simply “grape”. Hanging grapes everywhere!

Everyone also has a cerebellar uvula, which is right next to the cerebellar tonsils (more tonsils!) and at the end of the cerebeallar vermis (“cerebellar worm”). This area of the brain is involved in posture and locomotion.

In addition to both of those, males also have a uvula of the urinary bladder. This is less of a “little grape”, and more of a slight elevation in the internal urethral orifice, caused by the prostate.

Anatomy: Descriptive and Surgical. Gray’s Anatomy, 1918.
[illustration source]

Family problems experienced in childhood and adolescence affect brain development

New research has revealed that exposure to common family problems during childhood and early adolescence affects brain development, which could lead to mental health issues in later life.

The study led by Dr Nicholas Walsh, lecturer in developmental psychology at the University of East Anglia, used brain imaging technology to scan teenagers aged 17-19. It found that those who experienced mild to moderate family difficulties between birth and 11 years of age had developed a smaller cerebellum, an area of the brain associated with skill learning, stress regulation and sensory-motor control. The researchers also suggest that a smaller cerebellum may be a risk indicator of psychiatric disease later in life, as it is consistently found to be smaller in virtually all psychiatric illnesses.

Previous studies have focused on the effects of severe neglect, abuse and maltreatment in childhood on brain development. However the aim of this research was to determine the impact, in currently healthy teenagers, of exposure to more common but relatively chronic forms of ‘family-focused’ problems. These could include significant arguments or tension between parents, lack of affection or communication between family members, physical or emotional abuse, and events which had a practical impact on daily family life and might have resulted in health, housing or school problems.

Dr Walsh, from UEA’s School of Psychology, said: “These findings are important because exposure to adversities in childhood and adolescence is the biggest risk factor for later psychiatric disease. Also, psychiatric illnesses are a huge public health problem and the biggest cause of disability in the world.

“We show that exposure in childhood and early adolescence to even mild to moderate family difficulties, not just severe forms of abuse, neglect and maltreatment, may affect the developing adolescent brain. We also argue that a smaller cerebellum may be an indicator of mental health issues later on. Reducing exposure to adverse social environments during early life may enhance typical brain development and reduce subsequent mental health risks in adult life.”

The study, which was conducted with the University of Cambridge and the Medical Research Council Cognition and Brain Sciences Unit, Cambridge, is published in the journal NeuroImage: Clinical.

The 58 teenagers who took part in the brain scanning were drawn from a larger study of 1200 young people, whose parents were asked to recall any negative life events their children had experienced between birth and 11 years of age. The interviews took place when the children were aged 14 and of the 58, 27 were classified as having been exposed to childhood adversities. At ages 14 and 17 the teenagers themselves also reported any negative events and difficulties they, their family or closest friends had experienced during the previous 12 months.

A “significant and unexpected” finding was that the participants who reported stressful experiences when aged 14 were subsequently found to have increased volume in more regions of the brain when they were scanned aged 17-19. Dr Walsh said this could mean that mild stress occurring later in development may ‘inoculate’ teenagers, enabling them to cope better with exposure to difficulties in later life, and that it is the severity and timing of the experiences that may be important.

“This study helps us understand the mechanisms in the brain by which exposure to problems in early-life leads to later psychiatric issues,” said Dr Walsh. “It not only advances our understanding of how the general psychosocial environment affects brain development, but also suggests links between specific regions of the brain and individual psychosocial factors. We know that psychiatric risk factors do not occur in isolation but rather cluster together, and using a new technique we show how the general clustering of adversities affects brain development.”

The researchers also found at that those who had experienced family problems were more likely to have had a diagnosed psychiatric illness, have a parent with a mental health disorder and have negative perceptions of their how their family functioned.

Five mysteries of the brain

For centuries, the brain was a mystery. Only in the last few decades have scientists begun to unravel its secrets. In recent years, using the latest technology and powerful computers further key discoveries have been made.

However, much remains to be understood about how the brain works. Here are five important areas of study attempting to unlock the last secrets of the brain.

How to fix it

When we think, move, speak, dream and even love - it all happens in the grey matter. But our brains are not simply one colour. White matter matters too.

Much of the research into dementia has focused on the tell-tale plaques of beta amyloid and tau protein tangles which occur in the grey matter.

But one British scientist, Dr Atticus Hainsworth says the white matter - and its blood supply - may be equally important.

The white colour results from fatty sheaths around the axons - which are extensions of the nerve cell bodies and help the cells to communicate.

He is using banks of donated brains, in Oxford and Sheffield, to analyse white matter for potential triggers such as leaking blood vessels.

"Some of the cases had an MRI or CT scan and that information can help give more clues about whether there was disease in the white matter - and what its basis might be," says Dr Hainsworth.

If leaking blood vessels in white matter do play a key role in the development of dementia then it may offer up a another potential route for new drug therapies.

How to make us all geniuses


For years caffeine was used to enhance alertness. But popping a pill to get straight-A’s may soon become the norm.

At Cambridge University neuroscientist Barbara Sahakian is investigating cognitive enhancers - drugs which make us smarter.

She studies how they can improve the performance of surgeons or pilots and asks if they could even be used to make us more entrepreneurial.

But she warns that there is no long-term safety information on these drugs and as a society we need to talk about their use.

She says the scientific and ethical challenges created by drugs which affect the production of brain chemicals like dopamine and noradrenaline - which induce pleasurable or “fight or flight” responses - need to be debated in order to decide whether drug-tests become routine before taking an exam.

Dr Sahakian adds: “I frequently talk to students about cognitive-enhancing drugs and a lot of students take them for studying and exams.

"But other students feel angry about this, they feel those students are cheating."

How can we harness our unconscious?

People need to be on top of their game when mastering skills like playing a musical instrument or detecting a bomb.

But research suggests that our unconscious can be harnessed to help us excel.

Repeatedly playing a tricky piece of music obviously helps develop a familiarity with the bits that are most difficult.

But cellist Tania Lisboa, who’s also a researcher in the Centre for Performance Science at London’s Royal College of Music, says it also helps to send the trickier parts of a piece from her conscious to the unconscious part of her brain.

After hours of practice, a fluent musician’s brain stores how to play the piece in an area at the back of the brain called the cerebellum - literally “the little brain”.

Neuroscientist Prof Anil Seth, of Sussex University, says: “It has more brain cells than the rest of the brain put together.

"It helps to promote fluid movements.. So the conscious effort of learning how to bow a cello is moved from the cortical areas which are involved when it’s new or difficult over to the cerebellum, which is very good at producing unconscious fluent behaviour on demand."

Music and defence may not appear to have much in common, but the unconscious can also help detect potential threats, whether it’s a suspicious person in a crowd or the presence of an improvised explosive device.

The unconscious brain is really good at spotting patterns - a skill which Paul Sajda at Colombia University in New York exploits - right at the boundary of the conscious/sub-conscious.

"I can flash 10 images a second and if one of those images has something out of the ordinary..that will essentially cause me to re-orient my brain to that image - but I’m not exactly aware of what that is."

Brain activity is monitored whilst the analyst looks at images so that researchers can later see which images triggered reactions.

What dreams are for

It’s just 60 years since scientists in Chicago first noted the tell-tale “rapid eye movement” or REM sleep which we now associate with dreaming.

But our fascination with dreams dates back at least 5,000 years to ancient Mesopotamia when people believed that the soul moved out of a sleeping body to visit the places they dreamed of.

REM sleep - which occurs every 90 minutes or so - begins with signals from the base of the brain which eventually reach the cerebral cortex - the outer layer of the brain which is responsible for learning and thought.

These nerve impulses are also directed to the spinal cord, inducing temporary paralysis of the limbs.

Prof Robert Stickgold, from the Beth Israel Deaconess Medical Center for Sleep and Cognition in Boston, believes that dreams are vital for processing memory associations.

He has asked the subjects of some of his sleep studies to play Tetris - and then noted their descriptions of how they floated amongst geometric shapes in their dreams.

He’s an admirer of Japanese scanning research where the scientists could “read” the dreams of subjects as they had MRI scans.

But he says it’s hard to get people to sleep in a noisy, expensive scanner.

And the future? “I would like to see research which reveals the rules for dream construction - and how it relates to the larger concept of memory processing during sleep.”

One even more elusive goal: how to dream just happy dreams and ditch the bad ones, especially nightmares.

Can we cure unreachable pain?

Excruciating chronic pain is one of medicine’s most difficult problems to solve.

Untouched by conventional treatments like painkilling drugs, surgeons are now testing their theory that deep brain stimulation could provide relief.

It is a brain surgery technique which involves electrodes being inserted to reach targets deep inside the brain.

The target areas are stimulated via the electrodes which are connected to a battery-powered pacemaker surgically placed under the patient’s collar bone.

One of the pioneers of this technique is Prof Tipu Aziz at the John Radcliffe Hospital in Oxford.

Deep brain stimulation has been used in the past for Parkinson’s disease and depression, and is now being trialled on obsessive compulsive disorder patients as well as those in chronic pain.

One of his patients, Clive, has suffered from terrible pain for nearly a decade after an operation to remove a disc in his neck.

"Sometimes I thought that if I had an axe, I’d chop my own arm off, if I thought it would get rid of the pain."

The doctors explained to him that his brain was getting signals from his arm to his brain confused and that the electrodes could help.

In Clive’s case this was an area of the brain called the anterior cingulate.

A week after his surgery he was one of the fortunate 70% of patients for whom the deep brain stimulation provides relief.

"It’s great to be out of that pain now. Since having the implant I can sit down for longer, I am able to walk further, everything is an improvement."

Prof Aziz is treating medical conditions. But he is aware of ethical dilemmas which could arise if the technique was applied to other areas.

"Putting electrodes in targets to improve memory.

"Or you could put electrodes into people to make them indifferent to danger and create the perfect soldier."

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