The pull for lobotomy

The Psychologist has a fascinating article by historian Mical Raz on what patients and families thought about the effects of lobotomy.

Raz looks at the letters sent between arch-lobotomist Walter Freeman and the many families he affected through his use of the procedure.

Contrary to the image of the ‘evil surgeon who didn’t care about the harm he was doing’ many patients and families gave warm and favourable feedback on the effects of the operation.

Even some very worrying details about the post-operative results are recounted in glowing terms. Freeman had every reason to suspend his disbelief.

What it does illustrate is how a damaging and useless treatment could be perceived as helpful and compassionate by Freeman and, presumably, other doctors because of how docility and, in some cases, genuine reduced distress were valued above the person’s self-integrity and autonomy.

An interesting and challenging article.
 

Link to ‘Interpreting lobotomy – the patients’ stories’.

A multitude of phantoms

A fascinating paper in the neuroscience journal Brain looks at artistic depictions of phantom limbs – the feeling of the physical presence of a limb after it has been damaged or removed – and gives a wonderful insight how the brain perceives non-functioning or non-existent body parts.

In fact, most people who have a limb amputated will experience a phantom limb, although they often fade over time.

However, the feeling is usually not an exact representation of how the actual limb felt before it was removed, but can involve curious and sometimes painful ‘distortions’ in its perceived physical size, shape or location.

The Brain article looks at the diversity of phantom limb ‘shapes’ through their visual depictions.

The image on the left is from a 1952 case report where an amputation involved a ‘Krukenberg procedure‘.

This operation is rarely performed in the modern world but it involves the surgeon splitting the stump to allow pincer movements – and in this case it left the patient with the feeling of divided phantom hand.

In other cases, without any out-of-the-ordinary surgical procedure, patients can be left with a phantom that feels like the middle parts of their limb are missing while they still experience sensations in phantom extremities.

The drawing on the right was completed by a patient in a medical case study to illustrate their experience of a post-arm-amputation phantom limb.

In this case, the person experienced the feeling of a phantom hand on their shoulder stump, but had no experience of an intervening phantom arm.

While phantom limbs are usually associated with amputations, the phenomenon is actually caused by the mismatch between the lack of sensory input from the limb and the fact that the brain’s somatosensory map of the body is still intact and trying to generation sensations.

This means that any sensory disconnection, perhaps through nerve or spinal damage, can cause the experience of a phantom limb, even if the actual limbs are still there.

In the drawing on the left, a patient who suffered spinal damage that caused a loss of sensation in their limbs, illustrated how their phantom legs felt.

Although their own legs were completely ‘numb’ the phantom legs felt like they were bent at the knee, regardless of where their actual legs were positioned.

Normally, feedback from real world actions and sensations keeps the somatosensory map tied to the genuine size and shape of the body, but these sensations can begin to generate distorted sensations when this connection is broken through damage.

However, the stability of our experience of body size, shape and position is remarkably flexible in everyone as the rubber hand illusion shows.
 

Link to locked Brain article on depictions of phantom limbs.

The mysterious nodding syndrome – a crack of light

Two years ago we discussed a puzzling, sometimes fatal, ‘nodding syndrome‘ that has been affecting children in Uganda and South Sudan. We now know a little more, with epilepsy being confirmed as part of the disorder, although the cause still remains a mystery.

The condition affects children between 5 and 15 years old, who have episodes where they begin nodding or lolling their heads, often in response to cold. A typical but not exclusive pattern is that over time they become cognitively impaired to the point of needing help with simple tasks like feeding. Stunted growth is common.

Global Health News have a video on the condition if you want to see how it affects people.

In terms of our medical understanding, a review article just published in Emerging Infectious Diseases collates what we now know about the condition.

Firstly, it is now clear that epilepsy is part of the picture and the nodding is caused by recurrent seizures in the brain. This is a bit curious because this type of very specific ‘nodding’ behaviour has not been seen as a common effect of epilepsy before.

Also, knowing that it is caused by a seizure just pushes the need for explanation further down the causal chain. Seizures can occur through many different forms of brain disruption, so the question becomes – what is causing this epidemic form of seizure that seems to have a very selective effect?

With this in mind, a lot of the most obvious candidates have been ruled out. The following is from the review article, but if you’re not up on your medical terms, essentially, tests for a lot of poisons or infections have come up negative:

Testing has failed to demonstrate associations with trypanosomiasis, cysticercosis, loiasis, lymphatic filariasis, cerebral malaria, measles, prion disease, or novel pathogens; or deficiencies of folate, cobalamin, pyridoxine, retinol, or zinc; or toxicity from mercury, copper, or homocysteine.

Brain scans have been inconclusive with some showing minor abnormalities while others seem to show no detectable damage.

There have been some curious but not conclusive associations, however. Children with the nodding syndrome are more likely to have signs of infection by the river blindness parasite. But huge swathes of Africa have endemic river blindness and no nodding syndrome, and some children with nodding syndrome have no signs of infection.

Furthermore, the parasite is not thought to invade the nervous system and no trace of it has been found in the cerebrospinal fluid from any of the people with the syndrome. The authors of the review speculate that a new or similar parasite could be involved but hard data is still lacking and the typical signs of infection are missing.

A form of vitamin B6 deficiency is known to cause neural problems and has been found in affected people but it has also been found in just as many people untouched by the mystery illness. One possibility is this could be a risk factor, making people more vulnerable to the condition, rather than a sole cause.

One idea as to why it is so specific relates to the increasing recognition that some neurological conditions are caused by the body’s immune system erroneously attacking very specific parts of the brain.

For example, in Sydenham’s chorea antibodies for the common sore throat bacteria end up attacking the basal ganglia, while in limbic encephalitis the immune system attacks the limbic system.

This sort of autoimmune problem is a reasonable suggestion given the symptoms, but in the end, it is another hypothesis that is awaiting hard data.

Perhaps most mysterious, however, is its most marked feature – the fact that it only seems to affect children. At the current time, we seem no closer to understanding why. Similarly, the fact that it is epidemic and seems to spread also remains unexplained.

If you’re used to scientific articles, do check out the Emerging Infectious Diseases paper because it reads like a as-yet-unsolved detective story.

Either way, keep tabs on the story as it is something that needs to be cracked, not least because the number of cases seems to be slowly increasing.
 

Link to update paper in Emerging Infectious Diseases.

Year Four of the Blue Brain documentary

Film-maker Noah Hutton has just released the ‘Year Four’ film of the decade-long series of films about Henry Markram’s massive Blue Brain neuroscience project.

It’s been an interesting year for Markram’s project with additional billion euro funding won to extend and expand on earlier efforts and the USA’s BRAIN Initiative having also made it’s well-funded but currently direction-less debut.

Hutton also tackles Markram on the ‘we’re going to simulate the brain in 10 years’ nonsense he relied on earlier in the project’s PR push although, his answer, it must be said, is somewhat evasive.

Although more of an update on the politics of Big Neuroscience than a piece about new developments in the science of the brain, the latest installation of the Blue Brain documentary series captures how 2013 will define how we make sense of the brain for years to come.
 

Link to ‘Bluebrain: Year Four’ on Vimeo.
Link to the Bluebrain Film website.

Are men better wired to read maps or is it a tired cliché?

By Tom Stafford

The headlines

The Guardian: Male and female brains wired differently, scans reveal

The Atlantic: Male and female brains really are built differently

The Independent: The hardwired difference between male and female brains could explain why men are ‘better at map reading

The Story

An analysis of 949 brain scans shows significant sex differences in the connections between different brain areas.

What they actually did

Researchers from Philadelphia took data from 949 brain scans and divided them into three age groups and by gender. They then analysed the connections between 95 separate divisions of each brain using a technique called Diffusion Tensor Imaging.

With this data they constructed “connectome” maps, which show the network of the strength of connection between those brain regions.

Statistical testing of this showed significant differences between these networks according to sex – the average men’s network was more connected within each side of the brain, and the average women’s network was better connected between the two hemispheres. These differences emerged most strongly after the age of 13 (so weren’t as striking for the youngest group they tested).

How plausible is this?

Everybody knows that men are women have some biological differences – different sizes of brains and different hormones. It wouldn’t be too surprising if there were some neurological differences too. The thing is, we also know that we treat men and women differently from the moment they’re born, in almost all areas of life. Brains respond to the demands we make of them, and men and women have different demands placed on them.

Although a study of brain scans has an air of biological purity, it doesn’t escape from the reality that the people having their brains scanned are the product of social and cultural forces as well as biological ones.

The research itself is a technical tour-de-force which really needs a specialist to properly critique. I am not that specialist. But a few things seem odd about it: they report finding significant differences between the sexes, but don’t show the statistics that allow the reader to evaluate the size of any sex difference against other factors such as age or individual variability. This matters because you can have a statistically significant difference which isn’t practically meaningful. Relative size of effect might be very important.

For example, a significant sex difference could be tiny compared to the differences between people of different ages, or compared to the normal differences between individuals. The question of age differences is also relevant because we know the brain continues to develop after the oldest age tested in the study (22 years).

Any sex difference could plausibly be due to difference in the time-course of development between men and women. But, in general, it isn’t the technical details which I am equipped to critique. It’s a fair assumption to believe what the researchers have found, so let’s turn instead to how it is being interpreted.

Tom’s take

One of the authors of this research, as reported in The Guardian, said “the greatest surprise was how much the findings supported old stereotypes”. That, for me, should be a warning sign. Time and time again we find, as we see here, that highly technical and advanced neuroscience is used to support tired old generalisations.

Here, the research assumes the difference it seeks to prove. The data is analysed for sex differences with other categories receiving less or no attention (age, education, training and so on). From this biased lens on the data, a story about fundamental differences is also told. Part of our psychological make-up seems to be to want to assign essences to things – and differences between genders is a prime example of something people want to be true.

Even if we assume this research is reliable it doesn’t tell us about actual psychological differences between men and women. The brain scan doesn’t tell us about behaviour (and, indeed, most of us manage to behave in very similar ways despite large differences in brain structure and connectivity). Bizarrely, the authors seem also to want to use their analysis to support a myth about left brain vs right brain thinking. The “rational” left brain vs the intuitive’ right brain is a distinction that even Michael Gazzaniga, one of the founding fathers of “split brain” studies doesn’t believe any more.

Perhaps more importantly, analysis of how men and women are doesn’t tell you how men and women could be if brought up differently.

When the headlines talk about “hardwiring” and “proof that men and women are different” we can see the role this research is playing in cementing an assumption that people have already made. In fact, the data is silent on how men and women’s brains would be connected if society put different expectations on them.

Given the surprising ways in which brains do adapt to different experiences, it is completely plausible that even these significant “biological” differences could be due to cultural factors.

And even reliable differences between men and women can be reversed by psychological manipulations, which suggests that any underling biological differences isn’t as fundamental as researchers like to claim.

As Shakespeare has Ophelia say in Hamlet: “Lord, we know what we are, but know not what we may be.”

Read more

The original paper: Sex differences in the structural connectome of the human brain

Sophie Scott of UCL has some technical queries about the research – one possibility is that movements made during the scanning could have been different between the sexes and generated the apparent differences in the resulting connectome networks.

Another large study, cited by this current paper, found no differences according to sex.

Cordelia Fine’s book, Delusions of gender: how our minds, society, and neuro-sexism create difference provides essential context for looking at this kind of research.

UPDATE: Cordelia Fine provides her own critique of the paper

Tom Stafford does not work for, consult to, own shares in or receive funding from any company or organisation that would benefit from this article, and has no relevant affiliations.

The Conversation

This article was originally published at The Conversation.
Read the original article.

My punitive superego is lighting up my brain

This sentence actually appeared in the British Journal of Psychiatry:

Carhart-Harris et al’s finding of activation of Cg25 region of the cingulate gyrus in profound depression is consistent with the idea of an interpersonally isolated and punitive superego desperately trying to prevent overwhelming Pankseppian modalities impulses of panic and rage from reaching consciousness.

Find that in a dead salmon neuroscience haters!

This curious interpretation appeared in a letter in the BJP arguing for how neuroscience supports Freudian psychology.
 

Link to letter in the BJP.

A buried artefact

Sometimes there is an accidental beauty in the most macabre of events. Having a bullet lodged in your brain can produce beautiful CT scans due to the scanner’s difficulty with imaging metal objects.

The scan is from an 8-year-old girl who was hit by a bullet that was fired into the air in celebration. She was reportedly fine but this scan is from her hospital admission.

This pattern is an unintended consequence. It’s called a ‘streak’ or ‘star’ artefact and is caused by a combination of the CT scanner beam being over-absorbed by the dense metal object and the image construction software not being able to make sense of the incoming information correctly.

There’s various other images online if you want more unintended brain glitter.