The necessity of the brain: a slight return

This week’s edition of medical journal The Lancet has a brief case report of a 44-year-old man who was discovered to have a severely distorted brain, due to it being displaced by a build-up of fluid.

The man’s MRI scans are shown on the right and you can clearly see that huge sections of the brain are seemingly absent.

In this case, it was due to hydrocephalus, a condition where the cerebrospinal fluid (CSF) isn’t properly drained.

This fluid bathes and protects the brain. It is produced in the ventricles and circulates around before being removed into the blood supply.

If this draining doesn’t happen properly, the fluid builds up and dangerously increases the pressure inside the skull. This can lead to the brain being malformed, particularly if it occurs in childhood.

The young brain is remarkably good at adapting to obstacles. Children who have had half their brain removed can grow up with few obvious effects.

This seems to also occur in some cases of hydrocephalus. While it is usually associated with quite profound neurological problems, in some cases, it goes undetected because the people seem relatively unaffected.

The late neurologist John Lorber studied case of hydrocephalus and reported one particularly famous case.

A CT scan suggested that the patient had a largely fluid-filled skull with less than a few millimetres of grey matter, but with a IQ of 126 and a first class maths degree. Lorber had many other cases that he said illustrated similar effects.

Lorber provocatively titled his article ‘Is the brain really necessary?’.

His finding was quite astonishing and, despite some criticisms (CT scans probably exaggerate the damage and the patients undoubtedly had some mental difficulties), he highlighted the fact that the brain can adapt to quite severe setbacks in some exceptional cases.

However, the title of his article annoyed quite a few people and it has been cited as one of the origins of the ridiculous but curiously persistent myth that we only use 10% of our brains.

In comparison to Lorber’s case, the Lancet is a man described as having ‘normal social functioning’ and an IQ of 75, on the borderline of having a mild intellectual disability, but nothing so severe you wouldn’t find it as part of normal human variation.

Nevertheless, considering the extent of distortion in the brain, it’s still quite remarkable.

‘Distortion’ is likely to be the key is these cases, as the key brain areas are likely to be ‘smeared’ around the inside of the skull, rather than missing completely.

However, we shouldn’t be too complacent in our explanations of how some people can have such severe brain distortions while functioning really quite well. Our understanding of how this occurs is still quite poor. Plenty of mystery still accompanies these cases.

Link to (closed access) Lancet case report.
Link to write-up from Nature (via Neurophilosopher).
Link to excellent SciCon article on Lorber’s cases and the 10% myth.

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