Is the Brain Really Necessary?

Wednesday, September 12, 2007

Is the Brain Really Necessary?

Is the Brain Really Necessary?

(Or What and Where Is Consciousness)

This was the question asked by British neurologist John Lorber when he addressed a conference of pediatricians in 1980. Such a frivolous sounding question was sparked by case studies Lorber had been involved in since the mid sixties.

The case studies involve victims of an ailment known as hydrocephalus, more commonly known as water on the brain. The condition results from an abnormal build up of cerebrospinal fluid and can cause severe retardation and death if not treated.

Two young children with hydrocephalus referred to Lorber presented with normal mental development for their age. In both children, there was no evidence of a cerebral cortex. One of the children died at age three months, the second at twelve months was still following a normal development profile with the exception of the apparent lack of cerebral tissue shown by repeated medical testing. An account of the children was published in Developmental Medicine and Child Neurology.

Later, a colleague at Sheffield University became aware of a young man with a larger than normal head. He was referred to Lorber even though it had not caused him any difficulty. Although the boy had an IQ of 126 and had a first class honors degree in mathematics, he had "virtually no brain".

A noninvasive measurement of radio density known as CAT scan showed the boy's skull was lined with a thin layer of brain cells to a millimeter in thickness. The rest of his skull was filled with cerebrospinal fluid. The young man continues a normal life with the exception of his knowledge that he has no brain.

Although anecdotal accounts may be found in medical literature, Lorber is the first to provide a systematic study of such cases. He has documented over 600 scans of people with hydrocephalus and has broken them into four groups:

  • those with nearly normal brains.
  • those with 50-70% of the cranium filled with CSF
  • those with 70-90% of the cranium filled with CSF
  • and the most severe group with 95% of the cranial cavity filled with cerebrospinal fluid.

Of the last group, which comprised less than ten percent of the study, half were profoundly retarded. The remaining half had IQs greater than 100.

Skeptics have claimed that it was an error of interpretation of the scans themselves. Lorber himself admits that reading a CAT scan can be tricky. He also has said that one would not make such a claim without evidence.

In answer to attacks that he has not precisely quantified the amount of brain tissue missing, he adds, "I can't say whether the mathematics student has a brain weighing 50 grams or 150 grams, but it is clear that it is nowhere near the normal 1.5 kilograms."

Many neurologists feel that this is a tribute to the brains redundancy and it's ability to reassign functions. Others, however, are not so sure. Patrick Wall, professor of anatomy at University College, London states "To talk of redundancy is a copout to get around something you don't understand."

Norman Geschwind, a neurologist at Bostons Beth Israel Hospital agrees: "Certainly the brain has a remarkable capacity for reassigning functions following trauma, but you can usually pick up some kind of deficit with the right tests, even after apparently full recovery."

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