Sunday, March 06, 2005

Do You Need A Brain?

In the worlds of medicine and psychology,
neurobiology is enjoying tremendous popularity
and success by virtue of the many discoveries
concerning the roles of, among other things,
various classes of neurotransmitters, as well
as of neuromodulators such as endorphins,
enkephalins and neurohormones (neuropeptides)
in brain functioning. Some scientists are
claiming that the promised land of a complete
mapping of the brain with all its intricate
electrical and chemical pathways may be near
at hand.

As a result, age-old secrets underlying
consciousness, intelligence, language,
creativity, personality, sexuality, and
identity supposedly are being revealed almost
on a daily basis. For example, one popular
theory of brain functioning suggests there
is an increasing amount of evidence which
appears to indicate that all of the complex,
higher functions which traditionally have
been considered to distinguish human beings
from most, if not all, of other forms of life
on Earth, can be conceived as no more than
emergent properties arising out of the
trillions of interactions taking place
in the billions of synaptic junctions of
the nervous system - transactions which,
ultimately, are rooted in, or based on, the
activity of a fairly small number of
neurotransmitters and neuromodulators,
together with some relatively simple electrical
circuitry.

Roughly speaking, an emergent property is
a quality exhibited by a given system which
could not be predicted on the basis of just
looking at the basic components and processes
which tend to characterize that system. On
this view, the sheer number of interactions
entailed by the activity of a small set of
neurotransmitters, neuromodulators, along
with a few different modes of electrical
rhythms, is as important, if not more so,
than the biological components and kinds
of process which are interacting with one
another.

Concepts such as self-organizing systems,
reiteration, dissipative structures, non-
linear dynamics, chaos theory, parallel
processing, feedback, and so on are the watch-
words of the theory of emergent properties.
In effect, amazing new, unforeseeable,
qualitatively different functions are said
to be capable of arising out of the complexity
of interactions of a relatively small and
simple set of underlying components and
processes when these properties and processes
come together in the right set of conditions
which are governed by the principles inherent
in a confluence of, for example, non-linear
dynamics, dissipative structures, cybernetic
feedback systems, phase transitions, and so
on.

A number of years ago Karl Popper developed an
approach to the philosophy of science which came
to be known as "falsificationsim". Essentially,
Popper was concerned with the issue of how to
demarcate or distinguish defensible science from
metaphysical systems and/or pseudo-science.

Briefly stated, and in somewhat oversimplified
terms, the criterion which Popper settled on to
establish such a line of demarcation was the way
he believed the enterprise of science was rooted
in processes of empirical observation from which
one could deduce certain ideas, theories, and
possibilities that could, in turn, be tested
and, therefore verified - or not - when considered
against the backdrop of available evidence. More
specifically, he believed no number of positive
results from this sort of open-ended set of
empirical probes could prove a given theory, law,
or principle was true, but just one contra-
indication was enough to bring into question
the validity or truth of such a theory, principle,
or law.

Thus, Popper maintained the essence of science
resided in its tendency to focus in on the
challenge of falsification. In other words, the
test of a science - as opposed to metaphysical
speculation or pseudo-science - was the willingness
of a given instance of exploration to expose itself
to empirical, deductive judgements when measured
against available evidence by means of experiments
and tests which yielded data that could be shown
to be either consistent with that evidence or
falsified by it.

If a system of thought could not be falsified,
then, according to Popper, this was a strong
indication the conceptual framework in question
was more likely to be an instance of metaphysical
thinking or some sort of pseudo-science than it
was an exemplar of authentic scientific activity.
Similarly, if a given hypothesis, idea, theory or
law was shown to be falsified by experiment in
the context of available empirical evidence, then,
on this basis one had good reason either to reject
such a hypothesis in its entirety or to require
its proponent(s) to return to the drawing board
and re-work the hypothesis and/or theory in a way
that eliminated the aspect which had been falsified
through empirical demonstration.

As with most things in the philosophy of science,
there were both important insights contained in
Popper's idea of falsification, as well as problems.
In effect, when Popper's philosophical framework was
itself subjected to a rigorous round of falsification
by other philosophers of science, his system exhibited
a variety of lacunae and problems in the context of
available evidence concerning activities which were
considered to be part of "science" - both historically
as well as in some of its modern forms.

For present purposes, the ultimate validity of
Popper's system of thought is unimportant. What is
important is that he provides an idea - namely,
falsification - which can be used to help critically
reflect on the aforementioned theory of emergent
properties when the latter is applied to the
field of neurobiology.

For instance, what is one to make of the idea of
emergent properties when considered in relation to
the findings of Dr. John Lorber? Lorber is a British
clinician who, a number of years ago, generated some
interesting data which raises a lot of questions for
many facets of neurobiology - especially the theory
of emergent properties.

Dr. Lorber was working with people who were
hydrocephalic. These are individuals who have a
problem with the flow of cerebral-spinal fluid
in their nervous systems. Normally, cerebral-
spinal fluid flows in a continuos loop which
links the spinal column and the brain. Among
other things, this flow runs through a series
of four ventricles or cavities within the brain.

Sometimes - whether due to congenital defects
or post-birth trauma or a combination of the
two - a blockage arises at some point in the
flow of the cerebral-spinal fluid which causes
the fluid to accumulate in one or more of the
aforementioned ventricles. As more cerebral
spinal fluid is produced and accumulates in
this ventricle system, it begins to exert a
pressure on the brain.

Since the brain is surrounded by the skull
and, therefore, has no place to go, so to
speak, the pressure being exerted by the
cerebral-spinal fluid which is accumulating
in the brain's ventricle system begins to
compress the brain against the skull's
interior surface. Given enough time and/or
if - where possible - a shunt is not put in
place to relieve this pressure, the brain is
slowly squeezed into a volume consisting of
just a few millimeters spread around the
inner surface of the skull.

If the increasing pressure of accumulating
cerebral-spinal fluid is not relieved within
a certain critical time period through the
use of a shunt or other medical procedures,
the damage appears to be largely irreversible.
In fact, usually, the untreated effect of this
process of hydroencephaly is severe retardation.

I said "usually" above because Dr. Lorber
discovered some rather amazing exceptions to
the general rule. Some of the individuals who
suffered from hydroencephaly were quite normal
in their functioning, and there even were some
college graduates among this subset of exceptions.

For instance, one of the individuals in Lorber's
study had earned a honors degree in mathematics
at Cambridge University. Yet, when a scan was done
of this individual's head, the scan indicated that
almost the entire brain had been squeezed out of
existence. All that remained was an extremely thin
strip of neural matter running around the interior
of the skull casing. Lorber wrote up an overview
of his studies and submitted them for publication
in some reputable journals of science. His work
survived the peer review process and found its
way into print with titles such as "Do You Need
A Brain To Think?"

In the 19th century, the unfortunate Phineus
Gage made clinical history when he survived an
accident which resulted in an iron rod penetrating
his brain, only later to show marked changes in
personality, temperament and mental functioning.
These clinical findings were part of a vast array
of empirical data which accumulated during the next
century which indicated there seemed to be a very
strong relationship between the location of certain
kinds of brain trauma and the nature of dysfunctioning
in language skills, mental abilities, personality, and
so on which subsequently manifested themselves in these
individuals.

As outlined previously, Popper believed there was no
number of positive findings which could prove that a
given hypothesis or theory was true, but one finding
could falsify a theory or hypothesis. Thus, in the
present context, despite the fact there is an extremely
imposing array of data which ties brain functioning
to localization of brain activity, one has to ask
what is the significance of Lorber's clinical findings
with respect to hydroencephaly which appear to provide
some contra-indications to the idea that thinking, logic,
consciousness, understanding, and language are necessarily
"caused" by neurobiolgical activity?

Is there, somehow, sufficient brain matter left
intact in some of Lorber's hydrocephalic individuals
that they are capable of normal, if not above normal,
functioning? If so, why are the vast majority of
people who suffer from hydroencephaly severely
retarded? If so, what is the critical mass of
neural material which is necessary such that
below this amount, retardation occurs, and
above it, normal functioning ensues?

Is the difference between whether retardation
or normal functioning occurs a function of the
sequence of brain degradation in the sense that
one sequence of degradation leads to retardation,
while another sequence permits normal functioning?
Or, alternatively, since there is some evidence
indicating that sudden degradation of neurobiological
integrity leads to greater and longer-lasting
dysfunctioning than does the same (or sometimes
a greater) amount of degradation occurring over
a longer period of time, is the end result of
any given case of hydroencephaly a matter of
the amount of time which elapses before the
degradation process reaches its final state?

If, as Lorber's findings suggest, we don't
necessarily need a whole lot of neural matter
to function normally, then, why do we have
a three-pound universe residing above our
neck consisting of billions of cells and
trillions of interconnections? If, as
Lorber's findings suggest, brain functioning
is only "correlated" with higher mental
functioning, what are the "causes" of
such functioning?

Whatever the answer to the foregoing questions
may be, one idea would seem to be in need of
some re-working. More specifically, some of the
individuals in Lorber's studies - the ones
without most of their brains, and, yet, still
able to function normally (or better) - seem
to indicate that whatever causally underlies
our higher mental faculties, the hypothesis
of emergent properties would seem to have
been falsified in, at least, a few cases.

Presumably, in a brain which has been reduced
from roughly 1300-1700 cubic centimeters down
to a volume consisting of only a few millimeters
dispersed over the interior surface of the skull
casing, a substantial alteration has taken place
in the level of complexity of the system. In such
cases, one no longer necessarily has the same vast
number of intact cells and synaptic interactions
taking place within a few millimeters which had
been present in a full-volume brain.

If this is so, then, whatever the cause of our
higher cognitive functions may be, there appear
to be some instances of these abilities which do
not seem to be a function of so-called emergent
properties which arise out of the sheer number of
neural transactions which characterize a normal
brain. This does not mean emergent phenomena of
some sort do not occur in these contexts, but,
only that, one is going to have re-conceptualize
what is meant when one claims that higher cognitive
functions are an example of emergent properties in
action.

More specifically, one must come up with a fairly
specific explanatory framework of just how non-
linear dynamics, dissipative structures, phase
transitions, chaotic systems, reiterative processes,
and so on are capable of generating consciousness,
logical thought, understanding, language, and/or
creativity through just neurobiological activity.
Right now, the notion of emergent properties is
little more than a weak, metaphysical way of
confessing that we really have no idea how - or
even if - any of our higher cognitive abilities
arise out of the interaction of neurotransmitters,
neruomodulators, and neuronal electrical circuitry.

Yes, as is attested to by a great deal of medical
and scientific evidence, there is a definite
correlation between such neurobiological activity
and cognitive functioning. But, correlation is not
necessarily indicative of causality, and when one
has empirical data such as has been provided by John
Lorber which appears to falsify certain aspects of
the theory of emergent properties in neurobiology,
then one has a fairly clear warrant for re-thinking
this whole conceptual framework.

Anab Whitehouse

1 comment:

Anonymous said...

Brilliant!