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Neurology And Disorders Of The Nervous System
Patients always first undergo a neurological examination assessing their mental alertness, movements, postural reactions, spinal reflexes, cranial nerve function and pain sensitivity. Based on the examination, the problem can be traced to, for example, a specific area of the brain, the peripheral nervous system or part of the spine. Any necessary further investigations are then decided. Patients can also undergo MRI or CT scans.
Neurological disorders are divided into diseases of the central nervous system and diseases of the peripheral nervous system. The former include diseases in various parts of the brain as well as spinal cord issues, while the latter include diseases of the nerve roots, peripheral nerves and neuromuscular junctions as well as muscle diseases.
When investigating diseases of the peripheral nervous system, patients often give blood samples and undergo electromyograms and, if necessary, a conduction velocity measurement of peripheral nerves. The examinations conducted may also include samples of muscle or nerve tissue.
Diseases of the central nervous system are studied with a number of devices, such as MRI and CT. When suspecting epilepsy, EEG can also be used. An audiometer is used if deafness is suspected. In addition, the Veterinary Teaching Hospital's neurologists also perform brain and back surgery. At the neurology clinic, we also perform scanning under the official syringomyelia screening programme as well as BAER hearing tests.
Revealing The Genes That Shape The Human Brain
Christopher Walsh sat in the darkened auditorium, his heart racing, perched on the edge of his seat.
It was 1993, and Walsh, who had just set up his lab at Harvard Medical School, was at a conference in Venice, listening to a pediatric neurologist describe an extended family in which early brain development frequently went awry.
Affected members of that family were prone to epilepsy. Magnetic resonance imaging (MRI) revealed that in these individuals, neurons that belong in the cerebral cortex fail to migrate there from their birthplace deep inside the brain, leaving telltale blobs of misplaced neurons.
By studying four generations of this family, the speaker, Peter Huttenlocher, had found that girls inherited the disorder, called periventricular nodular heterotopia (PVNH), from their mothers. This helped narrow down the hunt for the faulty gene to the X chromosome—which includes just 10 percent of the genome. Walsh was certain that he could locate that gene.
"I wanted to be the first person to run up to him after his talk, because I imagined that everyone else in the audience was thinking the same thing: What a perfect way to study the genetics of the human brain."
Huttenlocher was happy to collaborate, and Walsh identified the mutant gene responsible for PVNH. To find more of these brain-altering genes, he began studying large families where the parents are genetically related and children have a greater chance of inheriting two flawed copies of genes that can jumble brain development.
Ultimately, he identified dozens of genetic mutations that alter brain function and the size and shape of the brain. Many underlie neurological conditions, from epilepsy and schizophrenia to autism spectrum disorders. In one dramatic example, the mutations create a cortical malformation dubbed a "double cortex" in females with this disorder, causing severe seizures and intellectual disability. By studying families with these mutations, Walsh uncovered key mechanisms underlying healthy brain development and revealed how these processes can be derailed by neurological disease.
Walsh and professors Jean-Louis Mandel, Harry Orr and Huda Zoghbi received the 2022 Kavli Prize in Neuroscience for their work.
Here, Walsh contemplates why psychiatric conditions are still so hard to comprehend, why structural anomalies don't necessarily derail mental function, whether genetics can give us a handle on consciousness, and how autism research could help reveal what makes us human.
How do mutations lead to schizophrenia and other psychiatric conditions?
As a neurologist, I think about the brain in terms of having localized functions. You've got an area for language and an area for vision. I was hoping that we might discover mutations that affect a particular part of the brain, but the genes disrupted in psychiatric disease tend to be genes that are expressed in all neurons. Yet schizophrenia is associated with specific, reproducible symptoms: Individuals hear voices, they become paranoid, they lose their ability to run thoughts together in a logical fashion. This favors the existence of some sort of circuit—but the circuit seems to be all over the place. So this is still an unanswered question.
Individuals with PVNH have blobs of neurons that are clearly in the wrong place. Yet some of these people are CEOs or medical students or computer programmers, and some have IQs of 140. Surprisingly, it looks like they are using those abnormally placed neurons to think. The neurons appear to be wired up to the regular cortex—sometimes in weird ways. It's just a completely different way of putting the brain together.
I sometimes think of the cerebral cortex as a part of the brain that evolved to dodge genetics. We have all these parts that are evolutionarily and functionally conserved, like the brainstem, the cerebellum, and the hypothalamus. Yet the cortex seems to be fairly unspecified in its design. It's like how you buy a big hard drive, thinking you'll figure out later what you'll do with it. The cortex is like the expansion slot on your computer.
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Illustration by Falconieri Visuals What makes our brains uniquely human? When it comes to understanding what makes us human, it seems like our best shot is to do it through the genome. By comparing our genome to the genomes of chimps and Neanderthals, we can look for "human-accelerated regions," which are conserved in our nearest neighbors but are a little different in humans. This suggests that they have an essential function but that in humans, that function might have changed a bit. There are thousands of these human-accelerated regions in our genome. We prioritize those that are mutated in neurological diseases. That's how nature identifies the parts of the genome that are critical: disruptions in those regions correspond with disease. Mutations in some human-accelerated regions are more common in children with autism spectrum disorder. So the study of medical genetics may give us the best chance we have of understanding human evolution—and autism may help us understand what makes us human.
What are the roots of consciousness?The whole idea that consciousness and behavior are mediated by a bunch of cells and chemicals—how is that even possible? In theory, if we knew that the mind or consciousness is unique to humans, then doing enough genome sequencing might allow us to identify segments that vary between humans and nonhumans. And that could give us a way to get at the question. The problem is, we don't even understand the mental processes of our fellow humans, much less how other animals experience the world. Our dog seems to have a sense of "personhood." Where in the brain does this sense of identity reside? I don't know, and I'm not sure that we have the experimental tools we need to tackle that problem. It remains a fascinating question.
To learn more about brilliant work of Kavli Prize laureates, visit kavliprize.Org. To explore more of the biggest questions in science, click here.
Wobbly Cat And The Cattle Dog: Kitten Born With Brain Disorder Strikes Up Unshakeable Bond With An Ageing Hound
Like any kitten, Ralphee is affectionate, playful and mischievous.
But it doesn't take long to spot that she is different from other cats and is unsteady on her feet because of an unusual neurological condition which is colloquially known as 'wobbly cat syndrome'.
The tabby can be seen waggling her head and sometimes jumping around uncontrollably, but is happy in the company of a protective cattle dog called Max.
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Feline unstable: Ralphee the pretty tabby cat (pictured) can be seen waggling her head and sometimes jumping around uncontrollably because a neurological disorder colloquially known as 'wobbly cat syndrome' but is happy in the company of a cattle dog called Max (pictured right)
HOW IS FELINE CEREBELLAR HYPOPLASIA CAUSED?The disorder is caused when a pregnant cat contracts feline distemper – a highly contagious and potential fatal vial disease.
It can result in cerebellum damage to unborn kittens as the virus passes from the mother cat to foetuses in her womb.
The earlier the mother cat contracts the disease in her pregnancy, the less likely the kittens are to survive – or the more serious their Feline CH will be.
Nature's natural enemies immediately became friends when Ralphee was rescued from a barn at a horse stable and came to live with the dog in Brisbane, Queensland, Australia.
The kitten has a neurological disorder called feline cerebellar hypoplasia (CH), which causes her to walk in an unusual way and wobble her head.
Some kittens are born with CH when their cerebellum – the part of the brain that controls coordination and fine motor skills – is underdeveloped.
The disorder develops inside the womb when a pregnant mother cat contracts feline distemper, which is a highly contagious and sometimes fatal viral disease.
Symptoms of the feline CH include: falling over for no apparent reason, a prancing, or high stepping walk and a general lack of balance, which can make it difficult for them to climb stairs.
Kitten's best friend: Ralphee has a neurological disorder called feline cerebellar hypoplasia (CH), which causes her to walk in an unusual way and wobble her head, but Max the dog watches over her
SYMPTOMS OF 'WOBBLY KITTEN SYNDROME'While Ralphee's owner says she is happy, loves affection and causes trouble wherever she goes, Max the dog is protective over his feline friend.
'Ever since Ralphee was brought home, Max is never far away. He appears to be forever curious and watches over Ralphee wherever she goes,' according to the Wakaleo YouTube channel.
'Ralphee is growing more mischievous by the day and loves to see what Max is doing as well. She will often get excited when he is nearby and leap in the air before playfully charging in his direction.'
Symptoms of the disorder include: falling over for no apparent reason, a prancing, or high stepping walk and a general lack of balance, which can make it difficult for cats like Ralphee (pictured) to climb stairs. Cats with the syndrome usually form close bonds with humans and animal companions like Max (also pictured)
Ralphee's owner says she is happy, loves affection and causes trouble wherever she goes, Max the dog is protective over his feline friend
While some people might be worried that animals with the condition are in pain - because they can appear to be walking gingerly and jerk around – they are not and their life expectancy is the same as an average cat's, according to the CH Cat Community.
The cats also have normal levels of intelligence, although they are often more dependent on humans and other animals, like Max, with whom they build strong bonds.
The condition is non-progressive and some owners of cats with CH have said it appears to improve as they get older, because the cats learn to deal with symptoms over time.
The photographer who filmed Ralphee told MailOnline that she does everything a normal cat does with a few minor differences.
'She has a room that has blankets and anything pointy or hard softened with pillows so when she stumbles out of her bed she is surrounded by soft items to keep her safe. This is more a precaution than anything.'
Kittens with 'wobbly cat syndrome' have normal levels of intelligence, although they are often more dependent on humans and other animals, like Max (pictured), with whom they build strong bonds
Mealtimes can be messy but the kitten manages better if her food is elevated. She is allowed to play outside if she is supervised by Max.
'There is a definite connection between Max and Ralphee. Max seems bothered when Ralphee wanders too far and will often remain at her side wherever she goes.
'I think he may be aware that Ralphee is different as he seems to look much like a concerned father observing his kids as they play in the pool. It's quite surreal.
'Ralphee, will sometimes chase Max and give him a playful swipe and play tough before giving him a nuzzle or rubbing along his legs. Max seems happy to entertain this behaviour,' he said.
While the kitten loves to pounce on leaves and enjoys chasing nuts around, her favourite playmate is Max, who doesn't seem to tire of her antics.
'People often feel sorry for cats with disabilities but for Ralphee and many others they seem to get along without even realising they are any different,' he said.
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