Wheww! I really wish you had broken this up into more manageable
packets and sent them one at a time!
(1) Everytime I am reminded of these "are brains necessary" examples, I
resolve to look more closely at evidence for "normality", and evidence
re what is or is not intact--regrettably, I am caught unprepared oone
more time. I will point out, however, that it has long been known that
hydrocephalic children with superficially normal behavior may show
deficits when examined neuropsychologically--for example, in subtle
language deficit alluded to in the expression "cocktail party speech"
(i.e. "correct" but rather empty), and in some visual-spatial problems
(e.g. constructional apraxia).
Same likely to be true with early hemispherectomy, I believe.
Still, to have any function at all with extreme anatomical abnormality
is remarkable, and does attest to difference between atypical
development and loss of structures after normal development.
re emotional anomalies if limbic connections damaged: how much do we
know about emotional status of specific cases? Might they be better
tolerated among mathematicians than in soome other groups and hence
re capacity to achieve "consciousness"--lacking a definition, don't
know, but I am struck by the ability of blind/deaf people (e.g. Helen
Keller) to achieve communication; ditto re-invention of (sign) language
by pairs of deaf children (for communication with each other).
(2) I am embarassed to hear of that "psychologist" saying the brain is
just 500% fat...
New York Neuropsychology Group
In <6p66cc$mbg$1 at hermes.bit.net.au> "Rugrat"
<johnhkm at logicworld.com.au> writes:
>> 22/07/98 23:31
>>Over recent years there have been many significant advances in the
>neurosciences but it seems to me that there still must be drawn a
>distinction between the findings of neuroscience, presently at least,
>the nature of human consciousness. No surprise there, but it irritates
>>Many years ago I saw a BBC special in which they interviewed a number
>adults (ages 18 -25) who had developed hydrocephalus as children and
>shunt installed. Performing CAT scans (I think) the researchers
>that a few of these individuals had suffered significant tissue loss
>shunt failure. One of the students, a 21 year old honours math student
>Birmingham University (I think, it was over 7 years ago), had less
>or third of the typical neocortex; although he did have a very rich
>supply to the remaining regions(signficant).
>>The CAT scans were fascinating as the tissue loss was obvious. I
>this to a psychologist once who tepidly replied, "Well, the brain is
>fat." The tissue loss involves both grey and white matter.
>important stuff, irrelevant. The issue is that there must have been a
>disruption of the internal pathways, although I doubt the corpus
>was damaged too much. Another consideration here is that 3 significant
>specialised) pathways only on the left hemi, the superior longitudinal
>fasciculus, the arcuate fasciculus, and the angular gryus, were also
>probably spared, but many thalamic connections and nuclei were
>also the frontal lobe-limbic (mesocortical?) connections were probably
>damaged. Given this and the likely limbic disruptions
>(hippocampus\amgydala?) I thought emotional anomalies would be
>amongst such patients.
>>The damage is gradual, and experiments have confirmed that a number of
>lesions is much less damaging than a single large lesion, the
>being that the brain can cope with the little disasters but is
>by the quick big one. There is evidence of stem and glial cell
>damaged areas. The problem in the above and other individuals is that
>sometimes the entire structure is gone, or at least incapable of being
>identified in these 'reconstituted' brains.
>>Interesting I thought but it was a TV progam after all. Norman Cook,
>Brain Code: Mechanisms of Information Transfer Across the Corpus
>makes mention of such anomalies and makes reference to their
>implications. Over the last few months more evidence, postings by
>(Anthro L, good archived discussion on it) who have witnessed similiar
>expressed some astonishment. I accept the reality that there are some
>people who by most current understandings should be dithering
>unpredictable unconscious automatons.
>>Given that in hominid evolution a great deal is made about the slowly
>increasing cerebral volume I find such examples frustrating. It does
>that we are developing a reasonable grasp on how normal brains develop
>when there is early childhood pathology the brain undertakes novel
>strategies to achieve its goals. In some cases it does this
>>It is as if the human brain, at a cellular level, or by some
>driven organisational level (hox genes? timeframes out?, modular,
>neurons [cf possible blindsight explanation],
>stimulus\topographical\symbolic processing,) is destined to achieve
>consciousness by whatever means. How's that for metaphysical. The
>childhood is very significant though, that's when real recovery can
>have noted some studies indicating that children who suffered from
>injury leading to asphasia, while often demonstrating an apparent full
>recovery, do display subtle signs of the old injury. And many people
>seemingly normal brains just aint that.
>>A possible escape ...
>>In one of the above examples I made reference to the rich blood supply
>the remaining tissue. In hydrocephalics the damage, I believe, is
>out, the arterial network may remain relatively intact, and given the
>incredible plasticity of brain blood supply, it is conceivable that
>remaining tissues receive a larger blood dose and so are are able to
>at an optimium level. It would be interesting to know if the current
>supply arrangements for the normal human brain are 'stretched to the
>Not meaning to sound sinister, but I wonder if these cerebrally
>individuals will be more likely to develop dementia through redundancy
>or at earlier ages. Do they suffer any volume shrinkage with age as
>normal brain does?
>>The problem for human brains may be that of supply and demand, even
>it already consumes 20% of everything @ 2% bodyweight it wants more or
>least could work a whole lot better if it had more. Intravenous
>injection provides an immediate IQ boost. Brain cell genes are also
>expressive in the human body, neurones are metabolically manic. Recent
>treatments for dementia etc have focussed on increasing oxygen supply
>brain. In one study many years ago oxygen enhancement was shown to
>significantly increase performance, but then lots of things seem to do
>This supports an ongoing mild nutrient deprivation idea.
>>Our cortices may have outgrown our heart, which has to work so hard to
>the blood up there. Bipedalism aint that old and we possess relatively
>brains. How would a giraffe manage with a similiar brain\bodyweight?
>existing system suggests that evolution has already gone to a great
>trouble to feed this hungry organ; an organ capable of generating its
>hunger. The brain is vulnerable to malnutrition, especially during
>>This is one way out of the problem, but it does suggest that the
>evolutionary mechanisms governing our cerebral construction are
>of step. This explains human history. It also allows the possibility
>significant increases in brain function are possible; although only
>some physical and\or genetic re-arrangement of bloody supply
mechanisms at a
>young age, an unpleasant prospect.
>>The above argument is also applicable to the question of brain
>Radiator Hypothesis" is a possible explanation for the rapid
>of the hominid line. Its basic premise is that the intricate bloody
>system also serves as a brain cooling system and walking on those hot
>African savannas made brains hot. Some larger African predators will
>hunt in the heat of the day; their metabolism isn't up to it. Maybe it
>gets too hot up there sometimes.
>>To steal Restak's title, The brain does have a mind of its own, even
>it has what we recognize as a mind it is heading towards creating one
>hook or by crook. If something gets in the way it seems capable of
>a set of hidden (?) strategies to find novel ways to achieve its goal.
>Brains aren't following our rules, they create the rules. I wonder if
>Neuroscience is faced with the unfortunate prospect of delineating how
>brains work by the history of each brain(or categories of), which
>that no single theoretic construction will be sufficient to fully
>how all brains do what they do.
>>An 'information processing' model may avoid this problem, but I
>this as a type of dualism unless the model's units are
>which is a problem with the hydrocephalics. The other thought here is
>each 'type' of brain may have its own type of basic information unit.
>don't think so though. Epistemologically terrifying.) The firings may
>same, but individuals may report different experiences for the same
>events. I believe studies have been conducted demonstrating such
>>Neurosurgeons report that each brain is unique, each constructed
>and not so slightly differently. (Which may explain above anomaly re
>report.) Consciousness is very old, not requiring a massive neocortex
>all, just a well fed one, particularly if you're on four legs and
>horizontal; or a sea mammal. There have been some animal studies
>which have strongly suggested (satisfactorily in my opinion) that a
>signficant number of mammals possess a style of consciousness, that
>different from our own, is nonetheless probably conscious at the
>experiential level. Now, where are those crystals ... . Someone please
>these dreams away. I'll stop because I need help.
>>Any assistance appreciated.
>johnhkm at logicworld.com.au>>>>>>>>>