Vitor Moura has called my attention to an article by Donald R. Forsdyke of the Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, Ontario, which appears in the latest issue of the journal Biological Theory (available online behind a paywall). Its title is "Wittgenstein’s Certainty is Uncertain: Brain Scans of Cured Hydrocephalics Challenge Cherished Assumptions￼￼￼￼."
Forsdyke, revisiting the work of British pediatrician John Lorber in the 1970s, finds a few more recent cases supportive of Lorber's controversial (to put it mildly) contention that very little gray matter is necessary in order to support normal mental function. Taking brain scans of hydrocephalics, Lorber found that in the most extreme cases, cerebrospinal fluid occupied "at least 95% of cranial capacity," leaving little room for brain tissue. Forsdyke writes:
Shocking enough. But now for what really rocked the neuroscientists. Half of Lorber’s 60 cases were of above-normal intelligence (as determined by standard IQ tests). The central scans in the figure [reproduced below]—virtually indistinguishable from the severely impaired case on the right—are representative of this group. And doubtless a candid camera would have caught Lorber’s jaw dropping when, among them, he found a student who was ‘‘socially completely normal’’ and had a first class honors degree in mathematics.
The math student's brain was estimated to weigh between 50 and 150 grams, while a normal brain would weigh 1.5 kilograms (1,500 grams).
Photo reproduced from the Discover blog post. The brain on the left is normal; the brain in the middle is that of a hydrocephalic patient who showed no sign of mental dysfunction; the brain on the right is that of a hydrocephalic who was severely impaired.
For decades Lorber's conclusions were largely ignored. But in 2007, The Lancet reported that a married civil servant with two children displayed a "massive ventricular enlargement" in his scans — essentially the same condition Lorber had observed decades earlier. Shortly afterward, another case along the same lines was reported by Brazilian neurosurgeons.
These cases remain exceedingly rare. Most hydrocephalics do not lead normal lives; their mental function is often severely compromised. But the existence of even a few such cases would seem to pose a challenge to the conventional wisdom in neurology.
Before we go on, though, we need to take note of an opposing view — namely, that these cases are less dramatic than they appear. In Discover magazine's blog, a contributor with the screen name Neuroskeptic argues that what is mainly missing in these scans is not gray matter, but white matter:
There’s no question that some of these brains are very striking. But I don’t think we need to throw out the textbooks yet.
While the enormous “holes” in these brains seem dramatic, the bulk of the grey matter of the cerebral cortex, around the outside of the brain, appears to be intact and in the correct place – this is visible as the dark grey ‘shell’ beneath the skull. What appears to be missing is the white matter, the nerve tracts that connect the various parts of the cerebral cortex with each other, and with the other areas of the brain.
However, some white matter is still visible as the pale grey layer that borders the holes. The big question is whether this layer of white matter is sufficient to connect up the grey matter and allow it to function normally. There doesn’t seem to be much of it, but on the other hand, we really don’t know how much white matter is strictly necessary.
I wonder also if the white matter might be denser than normal i.e. if the fibers were packed together due to being gradually compressed by the expanding fluid spaces?
After pointing out the need for more research, Neuroskeptic concludes:
In my view, these cases probably won’t require us to rethink neuroscience, although they do raise the issue of how much white matter is necessary. It may be that much of our white matter is redundant, which would be interesting, but not on a metaphysical level.
Getting back to Forsdyke, he devotes the rest of his article to arguing that the Lorber-type cases call into question the information-storage models of the brain. He rejects the idea that the brain can demonstrate unlimited plasticity:
... there must be rules for redundancy and plasticity. There must be limits. It is a matter of elementary logic that, at some stage of brain shrinkage, these explanations must fail. The drastic reduction in brain mass in the hydrocephalic cases seems to demand unimaginable levels of redundancy and/or plasticity—superplasticity. How much brain must be absent before we abandon these explanations and admit that the standard model, however incarnated, will not work?
The plasticity explanation is essentially what Neuroskeptic relies on. The skeptical argument is that the brain has so much "redundancy and/or plasticity" as to achieve "superplasticity" (Forsdyke's words). Thus even a loss of 95% of brain tissue is not necessarily catastrophic, as long as a "shell" of gray and white matter (the latter possibly compacted) remains intact. For Forsdyke, this explanation pushes plasticity/redundancy past the breaking point.
Instead, he's partial to a different, though admittedly speculative, idea:
Information relating to long-term memory is held outside the brain. Since most nonneural tissues and organs appear unsuited for this task, this extrapolates to long-term memory being outside the body—extracorporeal! Amazingly, this startling alternative has been on the table for at least two decades. A Georgetown University professor of computing science has sketched out how it might work (Berkovich 1993, 2014). A 10th century Arabic philosopher-physician even had a version (Avicenna 1631) ...
With respect to long-term memory, a stand-alone computer can be regarded merely as a terminal for manipulating data, and one retrieves from, and store files at, some remote location by way of the Internet. There are imaginative attempts to relate this to the workings of individual brains (Al Shargi and Berkovich 2009). The brain is seen as a receptor/transmitter of some form of electromagnetic wave/particle for which no obvious external structure (e.g., an eye) would be needed. Considering the universe as a holographic information storage device, and invoking the ‘‘spooky’’ physical principle of ‘‘non-locality’’ (Rudolph 2008), a ‘‘possible ‘hardware’ implementation’’ has been described (Berkovich 1993).
While various versions are considered in more detail elsewhere (Clark 2008; Noe ̈ 2009; Forsdyke 2011), they all fall far short on evidence. However, the rare hydrocephalic cases described here suggest that we should be cautious when tempted to cast aside the astonishing idea of personal information—long-term memory—being stored elsewhere ...
And, of course, when speaking of extracorporeal memory we enter the domain of ‘‘mind’’ or ‘‘spirit,’’ with corresponding metaphysical implications. ... Perhaps we should return to 1867 and harken to an exchange between two of Charles Darwin’s contemporaries, Robert Chambers and Alfred Russel Wallace: ‘‘My idea is that the term ‘supernatural’ is a gross mistake. We have only to enlarge our conceptions of the natural, and all will be alright’’ (Wallace 1905, pp. 285–286). We chuckle on learning how spiritualists duped such characters. Yet the possibility now emerges of at least some grains of truth amidst the dross that we poor creatures, imprisoned within the second decade of the 21st century, can understand no better than those imprisoned in the latter decades of the 19th could fathom ‘‘the missing five ounces’’ (Romanes 1887; Forsdyke 2014, 2015).
Though I don't think spiritualists necessarily "duped" the early researchers (my opinion is that some spiritualists were genuine and others were fraudulent, and many of the early researchers were quite adept at discerning between them), I welcome Forsdyke's willingness to look beyond the existing paradigm. As he himself says, it is somewhat astonishing that these cases have excited so little interest or curiosity. And even Neuroskeptic writes, "I’m surprised that more research hasn’t been done into this issue."
Forsdyke quotes philosopher Marek Majorek as being startled by the cognitive dissonance of experts reporting on the hydrocephalic cases without registering much of a reaction. Majorek wrote,
Yet it seems that the report should have been supplied with a large red title stating something to the effect ‘‘A major medical miracle: normal life with half a brain!’’, published not only in an academic journal but on the first pages of every major newspaper in the world, and extensively discussed in professional journals.
More than thirty years after Lorber's work, these anomalous cases still have not been explained. Perhaps even more astonishing, there seems to be very little interest in explaining them. They are unwanted, inconvenient scraps of data, duly reported and quickly filed away.
Hmm. Maybe he didn't need a brain, after all!