Neurophilosophy

The man with almost no brain

ra41982333.jpgThat the removal of an entire hemisphere of the brain can be performed with little or no noticable changes in behaviour is a demonstration of the remarkable adaptability of the human brain.

This procedure, known as a hemispherectomy, is a drastic measure taken to treat severe and intractable epilepsy.

If you think it incredible that someone with only half a brain can function normally, then you won’t believe this story from Yahoo News:

A man with an unusually tiny brain managed to live an entirely normal life despite his condition, caused by a fluid buildup in his skull, French researchers reported on Thursday.

Scans of the 44-year-old man’s brain showed that a huge fluid-filled chamber called a ventricle took up most of the room in his skull, leaving little more than a thin sheet of actual brain tissue.

Thanks to Bugs ‘n’ Gas Gal for emailing me a link to the story.

Update: Read more about this at Nature and New Scientist.

Comments

  1. #1 Tony P
    July 20, 2007

    So it’s true that we only use about 5% of our brain then.

    Actually I think I’ve met many people with only half a brain during my career.

  2. #2 Mo
    July 20, 2007

    It certainly is NOT true that we only use 5% of our brains. This is an example of brain plasticity – the remaining brain tissue has taken over the functions that would normally have been performed by the missing tissue.

  3. #3 Gerard Harbison
    July 20, 2007

    You left out the really funny bit, which is that the microbrained Frenchman worked in the French civil service for many years.

    Few other people have been as well qualified by nature to be bureaucrats.

  4. #4 Caledonian
    July 20, 2007

    This must have happened in very early childhood for the man to have lived.

    It makes one wonder – what is subtly missing from this man? We have the amount of brain that we do because it’s necessary – it’s expensive enough that evolution would have seen to that. It can’t all be redundancies.

  5. #5 The Neurocritic
    July 21, 2007

    So it appears that one can work as a French civil servant with an IQ of 75! The Yahoo article said the man was “NOT considered mentally retarded or disabled” but he was close:

    One common criterion for diagnosis of mental retardation is a tested intelligence quotient (IQ) of 70 or below.

  6. #6 Dr X
    July 21, 2007

    This must have happened in very early childhood for the man to have lived.

    This is ordinarily true when we are talking about brain trauma, but this is not a traumatic injury. This man had a shunt inserted to drain CSF during childhood, so it is unlikely that ventricular enlargement occurred until after the shunt was removed when he was age 14. The enlargement would have occurred extremely slowly over the course of many years in order to allow neural work arounds to develop in his more mature (less plastic) brain. Still, it is remarkable that he survived, was conscious and didn’t suffer from problems with regulation of vital functions (that we’ve heard) given the compression of his low brain structures. It doesn’t take a great deal of intracranial pressure to see serious symptoms.

    Referring to him as functioning normally, though, is probably a stretch. My bet is that he experienced symptoms that were not recognized over the years.

    Also, his FSIQ is 75 – hardly uncompromised. That puts him somewhere around the 5th percentile of intellectual functioning. I doubt the compromise in functioning is evenly distributed across functions. In any case, this was an extremely dull fellow and you would surely know it if you attempted to hold a conversation with him.

    It really is quite funny that he works as a civil servant. Maybe MRIs should be a standard part of pre-employment screening for all civil servants.

  7. #7 Jon H
    July 21, 2007

    “So it appears that one can work as a French civil servant with an IQ of 75!”

    I suspect ‘civil servant’ in France encompasses government jobs such as janitorial work, or other tasks which here would probably be outsourced to contractors. I doubt this guy was processing deeds or something like that.

  8. #8 Jon H
    July 21, 2007

    I wonder what the density of the remaining brain tissue is like. Did the pressure of the fluid kill the displaced brain cells, or was some or all of it simply compacted? If it’s more tightly packed than normal, there might be more brain matter there than is apparent. I suppose we won’t know for sure unless he wills his brain to science.

    Unfortunately, I bet this will be cited as evidence that Terri Schiavo could have recovered.

  9. #9 Michael Anes
    July 22, 2007

    Indeed, Jon H., just yesterday I ran across some older exchanges re: Schiavo, with just the objection you fear. The posters were commenting regarding John Lorber’s work with hydrocephalus patients, and one particular case from a while back in which a British mathematics student with an IQ of 126 showed the same type of brain tissue.

    I believe one provocative web page you can find, with scant details, is called “Is the brain really necessary?”

    The presumption, if I recall reading my primary Lorber sources in the literature correctly many years ago, is that there is still white matter and cortex there, it is just pressed to a great density – the whole brain is only 1-2 mm thick.

  10. #10 Herman King
    August 24, 2009

    The quesion is how common is such an occurrence. It must occur often, especially with members of congress.