Category: Inside the Brain

The Neurologist has a fascinating case report of a women with Parkinson’s disease who experienced a fluctuating belief that she didn’t exist.

Cotard’s delusion is usually described as the ‘belief that you’re dead’ although Jules Cotard, for whom the delusion is named, defined it as a délire des négations – the delusion of negation, or nihilism, as it’s usually translated.

In fact, in his original case report, Cotard’s patient didn’t believe they were dead but that they had “no brain, nerves, chest, or entrails, and was just skin and bone”.

This new case report in The Neurologist describes a patient with Parkinson’s disease who experiences something similar with the delusion appearing as their Parkinson’s medication began to wear off.

In December 2010, she went to follow-up visit accompanied by her caregivers and they reported that, in the last 2 months, the patient has developed a sudden onset of nihilistic delusion, mainly during the “wearing-off” condition and associated with end of dose dyskinesias and akathisia. The patient repeatedly complained of having lost both of her eyes, mouth, nose, and ears. Often during these events, she insisted to have a mirror to see herself. She expressed the false belief that she did not have the whole body and that nothing existed, including herself, without any insight. This nihilistic delusion, compatible with the diagnosis of Cotard syndrome, clearly improved with the administration of the following dose of levodopa and the associated amelioration of motor symptoms.

This is interesting because the Parkinson’s medication – levodopa – is a precursor to dopamine and is used to increase dopamine levels in the brain.

Increased dopamine levels in mid-brain areas are considered to be a key causal factor in generating the delusions and hallucinations of psychosis, but in this case delusions reliably appeared as dopamine levels were likely to have been dropping due to the medication wearing off.

Although this is a single case study, the effect was reliable when repeated, but it doesn’t mean that this would happen with everybody in the same situation.

But what it really shows is that the neurobiology of psychosis is not a simple ‘chemical imbalance’ but, in part, a complex dysregulation that can effect individuals differently due to the inherent interconnectedness of neural systems.
 

Link to PubMed entry for case report.

I’ve got a piece in today’s Observer about the amazing science of doing functional brain imaging and behavioural studies with babies while they are still in the womb to see the earliest stages of neurocognitive development.

Brain development during pregnancy is key for future health, which is why it gets checked so thoroughly during prenatal examinations. But neuroscientists have become increasingly interested in how the activity of the brain becomes progressively integrated and synchronised during development to support human experience, something developmental neuroscientist Moriah Thomason calls “bringing us closer to the blueprints of the brain”.

It’s difficult to state how remarkable this is, both technically and scientifically, as researchers have managed to measure the unborn brain in action as it responds to the outside world through the womb.

The article looks at how this science is developing and what it’s telling us about the earliest stages of the developing brain.

Exciting stuff.
 

Link to ‘Prenatal blueprints give an early glimpse of a baby’s developing brain’

A few extreme cases show that people can be missing large chunks of their brains with no significant ill-effect – why? Tom Stafford explains what it tells us about the true nature of our grey matter.

How much of our brain do we actually need? A number of stories have appeared in the news in recent months about people with chunks of their brains missing or damaged. These cases tell a story about the mind that goes deeper than their initial shock factor. It isn’t just that we don’t understand how the brain works, but that we may be thinking about it in the entirely wrong way.

Earlier this year, a case was reported of a woman who is missing her cerebellum, a distinct structure found at the back of the brain. By some estimates the human cerebellum contains half the brain cells you have. This isn’t just brain damage – the whole structure is absent. Yet this woman lives a normal life; she graduated from school, got married and had a kid following an uneventful pregnancy and birth. A pretty standard biography for a 24-year-old.

The woman wasn’t completely unaffected – she had suffered from uncertain, clumsy, movements her whole life. But the surprise is how she moves at all, missing a part of the brain that is so fundamental it evolved with the first vertebrates. The sharks that swam when dinosaurs walked the Earth had cerebellums.

This case points to a sad fact about brain science. We don’t often shout about it, but there are large gaps in even our basic understanding of the brain. We can’t agree on the function of even some of the most important brain regions, such as the cerebellum. Rare cases such as this show up that ignorance. Every so often someone walks into a hospital and their brain scan reveals the startling differences we can have inside our heads. Startling differences which may have only small observable effects on our behaviour.

Part of the problem may be our way of thinking. It is natural to see the brain as a piece of naturally selected technology, and in human technology there is often a one-to-one mapping between structure and function. If I have a toaster, the heat is provided by the heating element, the time is controlled by the timer and the popping up is driven by a spring. The case of the missing cerebellum reveals there is no such simple scheme for the brain. Although we love to talk about the brain region for vision, for hunger or for love, there are no such brain regions, because the brain isn’t technology where any function is governed by just one part.

Take another recent case, that of a man who was found to have a tapeworm in his brain. Over four years it burrowed “from one side to the other“, causing a variety of problems such as seizures, memory problems and weird smell sensations. Sounds to me like he got off lightly for having a living thing move through his brain. If the brain worked like most designed technology this wouldn’t be possible. If a worm burrowed from one side of your phone to the other, the gadget would die. Indeed, when an early electromechanical computer malfunctioned in the 1940s, an investigation revealed the problem: a moth trapped in a relay – the first actual case of a computer bug being found.

Part of the explanation for the brain’s apparent resilience is its ‘plasticity’ – an ability to adapt its structure based on experience. But another clue comes from a concept advocated by Nobel Prize-winning neuroscientist Gerald Edelman. He noticed that biological functions are often supported by multiple structures – single physical features are coded for by multiple genes, for example, so that knocking out any single gene can’t prevent that feature from developing apparently normally. He called the ability of multiple different structures to support a single function ‘degeneracy’.

And so it is with the brain. The important functions our brain carries out are not farmed out to single distinct brain regions, but instead supported by multiple regions, often in similar but slightly different ways. If one structure breaks down, the others can pick up the slack.

This helps explain why cognitive neuroscientists have such problems working out what different brain regions do. If you try and understand brain areas using a simple one-function-per-region and one-region-per-function rule you’ll never be able to design the experiments needed to unpick the degenerate tangle of structure and function.

The cerebellum is most famous for controlling precise movements, but other areas of the brain such as the basal ganglia and the motor cortex are also intimately involved in moving our bodies. Asking what unique thing each area does may be the wrong question, when they are all contributing to the same thing. Memory is another example of an essential biological function which seems to be supported by multiple brain systems. If you bump into someone you’ve met once before, you might remember that they have a reputation for being nice, remember a specific incident of them being nice, or just retrieve a vague positive feeling about them – all forms of memory which tell you to trust this person, and all supported by different brain areas doing the same job in a slightly different way.

Edelman and his colleague, Joseph Gally, called degeneracy a “ubiquitous biological property … a feature of complexity”, claiming it was an inevitable outcome of natural selection. It explains both why unusual brain conditions are not as catastrophic as they might be, and also why scientists find the brain so confounding to try and understand.

My BBC Future column from before Christmas. The original is here. Thanks to everyone on twitter who chipped in on the plural of cerebellum

I’ve written a piece for the new PLOS Neuro Community about how the social aspects of hallucinated voices tend to be ignored and how we might go about making it more central in psychology and neuroscience.

It came about because the PLOS Neuro Community have asked authors of popular papers to write a more gentle introduction to the topic, so the piece is based on a PLOS Biology paper I wrote last year.

I’ve met a lot of people who hear hallucinated voices and I have always been struck by the number of people who feel accompanied by them, as if they were distinct and distinguishable personalities. Some experience their hallucinated entourage as hecklers or domineering bullies, some as curious and opaque narrators, others as helpful guardians, but most of the time, the voice hearer feels they share a relationship with a series of internal vocal individuals.

The piece discusses psychology and neuroscience but in the post, I also mention some work I’ve been doing with philosopher of mind Sam Wilkinson. As luck would have it, Sam just published a post about what we’re working on, on the excellent Imperfect Cognitions blog.

It looks at hallucinated voices and the representation of agency and agents. If you’re not used to these terms they can be slightly opaque but they refer to how the mind and brain represents autonomous individuals – be they human, animal, presumed or imaginary – and how that might relate to the experience of having hallucinated voices.
 

Link to A Social Visit with Hallucinated Voices.
Link to The Representation of Agents in Auditory Verbal Hallucinations.

Neurology journal Neurocase has an interesting study of a women who started compulsively writing poetry after having brief epileptic amnesia treated with the anti-seizure drug lamotrigine.

A 76-year-old woman reported having a poor memory and short periods of disorientation and was eventually diagnosed with transient epileptic amnesia – brief recurrent seizures that lead to short periods where affected people can’t lay down new memories.

Several months after starting lamotrigine [a common and widely used anti-seizure drug], the patient suddenly began to write original verse. Whereas poetry had never previously been among her pastimes, she now produced copious short poems (around 10–15 each day) on quotidian topics such as housework or about the act of versifying itself and sometimes expressing her opinions or regret about past events. These poems often had a wistful or pessimistic nature but did not have a moral or religious focus. Her husband characterized them as “doggerel” because they were generally rhyming and often featured puns and other wordplay.

My poems roams,
They has no homes
Yours’, also, tours,
And never moors.

Why tie them up to pier or quay?
Better far, share them with me.

Prose – now, that’s a different matter.
Rather more than just a natter.
Prose is earnest, prose is serious
Prose is lordly and imperious
Prose tells you, loud, clear, that
Life – life is dear.

This versifying had a compulsive quality: she spent several hours per day writing poetry and became irritated if attempts were made to disengage her. However, she appeared to derive pleasure from the activity and there was no evidence of associated distress. She did not produce prose passages, diaries, or other examples of hypergraphia, nor did she develop new interests in other “creative media,” such as visual arts or music.

When reassessed 6 months after the onset of versifying this apparent compulsion had diminished, but she continued to produce occasional poems. She had also developed a more general fondness for wordplay, frequently using puns in speech, making humorous word associations, and identifying word patterns in everyday objects such as car license plates. Throughout this period there were no associated mood symptoms, features of a thought disorder, or other changes in her behavior or cognition to suggest hypomania or another generalized neuropsychiatric disturbance.

The article mentions the exclusion of hypomania and thought disorder because these are two other phenomena that appear as compulsive rhyming or punning in speech.

The article also mentions some similarities between the compulsive poem writing and hypergraphia – compulsive and copious writing that is a well-known although not particularly common symptom of epilepsy.

The difference in this case, however, is that hypergraphia often appears as meaningless, rambling or disorganised, and this particular patient produced competent, if not particularly high quality poems.

One of the most interesting implications of these cases is that rhyming, punning and poetic speech, which we normally think of as something that needs specific conscious effort and attention, can appear spontaneously to the point of overwhelming our normal forms of communication.
 

Link to open-access scientific article.
Link to DOI of same.

I’ve got an article in The Observer about how, a little surprisingly, the dead are becoming an increasing focus for brain scanning studies.

I first discussed this curious corner of neuroscience back in 2007 but a recent Neuroskeptic post reminded me of the area and I decided to check in on how it’s progressing.

It turns out that brain scanning the dead is becoming increasingly common in research and medicine and the article looks at how the science is progressing. Crucially, it’s helping us better understand ourselves in both life and death.

For thousands of years, direct studies of the human brain required the dead. The main method of study was dissection, which needed, rather inconveniently for the owner, physical access to their brain. Despite occasional unfortunate cases where the living brain was exposed on the battlefield or the surgeon’s table, corpses and preserved brains were the source of most of our knowledge.

When brain scanning technologies were invented in the 20th century they allowed the structure and function of the brain to be shown in living humans for the first time. This was as important for neuroscientists as the invention of the telescope and the cadaver slowly faded into the background of brain research. But recently, scrutiny of the post-mortem brain has seen something of a revival, a resurrection you might say, as modern researchers have become increasingly interested in applying their new scanning technologies to the brains of the deceased.

It’s a fascinating area and you can read the full article at the link below.

UPDATE: I’ve just noticed two of the links to studies have gone AWOL from the online article. The study that looked for the source of a mysterious signal by scanning people, cadavers and dummies and found it was a scanner problem was this one and the study that used corpses to test in-scanner motion correction was this one.

 

Link to Observer article on brain scanning the dead.

I’ve got an article in The Observer about how the science of lucid dreaming is being pushed forward by the development of ‘in-dream’ experiments.

A lucid dream is where you become aware you are dreaming and where you can potentially change elements of the dream as it happens.

The piece discusses how eye movements allow communication from within dreams to researchers in the sleep lab and how this has led to studies involving people doing experimental tasks in the dream world.

One of our most mysterious and intriguing states of consciousness is the dream. We lose consciousness when we enter the deep waters of sleep, only to regain it as we emerge into a series of uncanny private realities. These air pockets of inner experience have been difficult for psychologists to study scientifically and, as a result, researchers have mostly resorted to measuring brain activity as the sleeper lies passive. But interest has recently returned to a technique that allows real-time communication from within the dream world.

The article also touches on the ‘dream hacking’ community who borrow from the scientific literature to try an increase their chances of having a lucid dream, sometimes using psychiatric medication for which vivid dreams are considered a side-effect.

The full piece is at the link below.
 

Link to article in The Observer.

My time in the BPS Research Digest hotseat continues. Today’s post is about a lovely study by Stuart Ritchie and colleagues which uses a unique dataset to look at the effect of alcohol on cognitive function across the lifespan. Here’s the intro:

The cognitive cost or benefit of booze depends on your genes, suggests a new study which uses a unique longitudinal data set.

Inside the laboratory psychologists use a control group to isolate the effects of specific variables. But many important real world problems can’t be captured in the lab. Ageing is a good example: if we want to know what predicts a healthy old age, running experiments is difficult, even if only for the reason that they take a lifetime to get the results. Questions about potentially harmful substances are another good example: if we suspect something may be harmful we can hardly give it to half of a group of volunteer participants. The question of the long-term effects of alcohol consumption on cognitive ability combines both of these difficulties.

You can read the rest here: Alcohol could have cognitive benefits – depending on your genes.

See also, Tuesday’s post: A self-fulfilling fallacy?