“Is Your Brain Really Necessary? John Lorber, a British Neurologist, Claims That Some Patients Are More Normal Than Would Be Inferred from Their Brain Scans”, 1980-12-12 (; backlinks; similar):
…Lorber was not jesting totally when he addressed a conference of pediatricians with a paper entitled “Is your brain really necessary?” Lorber believes that his observations on a series of hydrocephalics who have severely reduced brain tissue throws into question many traditional notions about the brain, both in clinical and scientific terms.
“There’s a young student at this university”, says Lorber, “who has an IQ of 126, has gained a first-class honors degree in mathematics, and is socially completely normal. And yet the boy has virtually no brain.” The student’s physician at the university noticed that the youth had a slightly larger than normal head, and so referred him to Lorber, simply out of interest. “When we did a brain scan on him”, Lorber recalls, “we saw that instead of the normal 4.5-centimeter thickness of brain tissue between the ventricles and the cortical surface, there was just a thin layer of mantle measuring a millimeter or so. His cranium is filled mainly with cerebrospinal fluid.”
…In young children, whose skulls are still malleable, one obvious consequence can be a grossly enlarged head. Additionally, this physical assault from within leads to a real loss of brain matter. It is therefore not surprising that many hydrocephalics suffer intellectual and physical disabilities. What is surprising, however, is that a substantial proportion of patients appear to escape functional impairment in spite of grossly abnormal brain structure.
“The spina bifida unit at the Children’s Hospital here in Sheffield is one of the largest in the world”, explains Lorber, “and this gives us an opportunity to make many observations. Since the introduction of the safe, noninvasive brain scanning technique just a few years ago we have done more than 600 scans on patients with hydrocephalus.” Lorber divides the subjects into four categories: those with minimally enlarged ventricles; those whose ventricles fill 50 to 70% of the cranium; those in which the ventricles fill 70–90% of the intracranial space; and the most severe group, in which ventricle expansion fills 95% of the cranium. Many of the individuals in this last group, which forms just less than 10% of the total sample, are severely disabled, but half of them have IQ’s greater than 100. This group provides some of the most dramatic examples of apparently normal function against all odds.
Commenting on Lorber’s work, Kenneth Till, a former neurosurgeon at the Great Ormond Street Hospital for Sick Children, London, has this to say: “Interpreting brain scans can be very tricky. There can be a great deal more brain tissue in the cranium than is immediately apparent.” Till echoes the cautions of many practitioners when he says, “Lorber may be being rather overdramatic when he says that someone has ‘virtually no brain.’” Lorber acknowledges the problem of interpretation of brain scans, and he counters Till’s remarks by insisting, “Of course these results are dramatic, but they’re not overdramatic. One would not make the claim if one did not have the evidence.”
…Lorber concludes from these observations that “there must be a tremendous amount of redundancy or spare capacity in the brain, just as there is with kidney and liver.” He also contends that “the cortex probably is responsible for a great deal less than most people imagine.” These are two areas of considerable dispute in neurobiology. Wall lends support for this second point. “One reason why results such as Lorber’s have been neglected for so long is because of the implied attack on the predominance of the cerebral cortex”, suggests Wall. “For hundreds of years neurologists have assumed that all that is dear to them is performed by the cortex, but it may well be that the deep structures in the brain carry out many of the functions assumed to be the sole province of the cortex.” He likens the cortex to a “reference library” that may be consulted from time to time.
On the question of the brain’s spare capacity there is equal contention. “To talk of redundancy in the brain is an intellectual cop-out to try to get round something you don’t understand”, states Wall. Geschwind 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.” However, Colin Blakemore, professor of physiology at Oxford University, England, sees spare capacity as an important quality of the human brain. “The brain frequently has to cope with minor lesions and it’s crucial that it can overcome these readily”, he says; “there may be some reorganization of brain tissue, but mostly there’s a reallocation of function.”
It is perhaps important that many of the instances in which gross enlargement of cerebral ventricles is compatible with normal life are cases where the condition develops slowly. Gross surgical lesions in rat brains are known to inflict severe functional disruption, but if the same damage is done bit by bit over a long period of time, the dysfunction can be minimal. Just as the rat brains appear to cope with a stepwise reduction of available hardware, so too do the human brains in some cases of hydrocephalus…The sparing of the gray matter even in severe hydrocephalus could go some way to explaining the remarkable retention of many normal functions in severely affected individuals.