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
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
Anthony Smith "The Mind" New York
Viking Press, 1984, p.230
Roger Lewin "Is Your Brain Really Necessary?"
Science 210 December 1980, p. 1232