By Robert DePaolo
Abstract
This article discusses the hyper-inhibitory and spiked movement
fluctuations that typify autism in the context of human brain evolution;
specifically the origin of a dualistic integrating/sequencing
(“get-set”) mental capacity that otherwise facilitates internal
cognition, self- regulation and language processing.
While many diagnostic aspects of autism have been well documented,
some remain fairly obscure yet meaningful in considering the cause of
the disorder. For example, the well-respected Gilliam Autism Rating
scale includes questions about various aspects of autism such as
stereotypy, inappropriate social behaviors, sensory behaviors and
language deficiencies. Only one item on the questionnaire refers to
“darting behavior” yet this autistic movement pattern might ultimately
explain a great deal about the origin and nature of the disorder.
As McFabe (2009) and Redlich, Cueli et. al. (2002) have noted,
autistic individuals tend to display particular movement anomalies.
Actually since it pertains to more than motor functions it might be
called a functional anomaly. It is characterized by abrupt alternations
extreme inhibition and “drift” similar to the waxy flexibility seen in
catatonia, and abrupt, spiked activation like the “darting” behavior
mentioned in the GARS. Much of the duress experienced by autistic
individuals results from having to go from states of non-responsiveness
to hyper-activation in rapid time frames in the course of every
behavioral or cognitive effort. Such a tendency would seem to indicate
that autism is typified by, among other things, lack of a preparatory
mechanism within the central nervous system that would otherwise
modulate between low-inhibitory and high-excitatory states. If so, that
would make virtually all experiences potentially aversive and it might
explain why many autistic individuals lack motivation to engage in
social activities, (Schultz, Kohl et al 2012) are prone to physical
fatigue (Shoffner 2008 ), have low task endurance (Koldewyn, Swallow
2011) and find high stimulus interactions such as eye contact aversive (
Doherty-Sneddon (2012), (Burns, 2012)..
In that context, one might surmise that the behavior patterns
associated with autism, for example stereotyped movements, preference
for stimulus monotony, vocalization patterns and social avoidance are
adaptations to duress; specifically a life of endless surprises and
abrupt arousal/somatic shifts. It might also explain why some autistic
individuals exhibit pockets of brilliance. Perhaps in some instances
there is enough predictability over their environment to preclude the
need for ‘preparatory activities” …here used in place of “sensory” or
“stereotyped” behaviors. When able to focus on the external world they
can take self-regulation for granted and learn more efficiently.
In that sense this would imply that autism can be defined as a
condition within the central nervous system involving a pan-resistance
to experience that blocks the capacity to process information from the
outside world.
There isn’t necessarily anything new in that statement. The research
results of Belmonte and Yurgelun (2003) which point to shifts between
under inclusive and over-inclusive perceptual processing would predict
the same. The difference is that the massive shifts in arousal can be
viewed as more than perceptual. Indeed they can be said to influence
movement, perception, memory, emotion and all faculties. Whether
feeling, sensing, behaving or communicating the autistic individual is
forced to undergo discomforting accelerations in all
psycho-physiological functions. Yet while that paradigm might help
explain some aspects of the “what” in autism. The “why’ is a bit more
complex.
In the Beginning
It is interesting to note that upon initial referral to evaluators or
physicians, many parents express the greatest concern about lack of
language development and social awareness. As discussed above, many
diagnostic tests revolve around such topics and the presence of those
traits in autism is well documented. Yet upon deeper questioning,
specifically; what was the very first thing you noticed about your child
that led you to think something might be wrong; the parent frequently
refers to a state of lethargy. They might assert that their child seems
to be in a sleepy state, is non responsive to stimuli, displays an
excessively flexible head carriage, body and sitting posture. As with
speech and cognition, the soma seems un-stabilized by a modulating
mechanism. In such cases it is the lack of energy that first stands out
as a sign of atypical development. These parents often compare the
behavior of their child with that of other children. They recall that
other babies sitting in a shopping cart at the supermarket always look
at strangers, often make faces, smile, seem enchanted by the external
world. More to the point, these children are energized and have the
ergonomic capacity and efficiency to interact and take pleasure from the
interaction, whereas their child exhibits a certain limpness.
Using the initial stags of child development as a guide it might make
sense to presume the natural/pathogenic state of autism lies in that
trend toward limpness, or in less colloquial terms, extreme mind-body
lethargy. Yet abrupt arousal and movement fluctuations and lethargy are
in many ways, opposites. Thus the question becomes, is the relatively
non-responsive state a result of lethargy or is it due to input flooding
that serves to block response selection and attention? In other words
is the autistic child extremely tired or extremely uncertain?
Some research has shown that energy deficiencies are indeed one
component of autism. For example Rudacile (2011) has implicated
mitochondrial dysfunction as a possible factor in the onset of the
disorder – mitochondria being the engines within cells enabling them to
process and metabolize sugars and other nutrients in converting them to
energy and behavior. On the other hand behavior cannot occur unless
there is some capacity for stimulus discrimination and flooding would
prevent that. Energy depletion is involved in some way but the
chicken-egg model applies here. Does energy enable the person to control
overload or is it a byproduct of the sensory work involved in trying to
parse flooded inputs without adequate parsing capacities to begin with?
Beyond that is the question of how this all pertains to human brain
function in general. To address that question it might be interesting to
take a look back at human brain evolution to see how our perceptions,
language, movement style and general psychology became quintessentially
human.
A Tale of Ancestral Integration
If, as most paleo-anthropologists assume, human evolution derives
from primate origins then we are the descendants of tree-dwellers. All
arboreal primates have eyes situated in front, i.e have stereoscopic
vision, enabling them to utilize depth perception – a most important
faculty in leaping among branches high up in the forest canopy. Thus in
the most basic sense the primate brain is a centralizing structure, able
and inclined to take disparate neuronal inputs and collate them into a
core perceptual-motor skill. For early primates that facilitated not
only efficient branch-swinging but also set the stage for inter-group
acoustical communications by which to issue warnings about approaching
predators like snakes and eagles. Group communication is inherently
integrative because in order for the signals to be recognizable to all
members they had to be rule-governed. Thus the social-interactive
prowess of the primate conceivably resulted from the same neural
tendency toward integration that facilitated stereoscopic vision. It
seems to have been a classic example of what Darwin called a
“conversion”
Integration is essentially synonymous with “aiming.” Thus primate
brain evolution ran parallel to the enhancement of various “aiming”
faculties.. Aiming is a good thing, but like all other adaptations it
comes with a cost. Aiming entails such a recruitment of neural inputs
that it has the potential to a flood the brain – like a terminal with
too many trains arriving at the same time. Flooding can produce
confusion, but since arboreal primates use this function successfully it
is hard to describe such a brain model as a liability. In fact, for
arboreal primates it is not.
On the other hand that might be because while their brains are large
compared to most other creatures, they are much smaller than the human
brain. Flooding in a smallish brain is not nearly as confusing as it is
in a large brain. Once the early human brain reached its current size
and structure other internecine, systemic and neurological adaptations
had to occur to prevent mass neural confusion. As if to solve the
problem of integration-induced overload, the human brain began to erect
parsing barriers. Hemispheric differentiation was one such mechanism. It
separated experience into a linguistic and sequential (left-hemisphere)
vs. holistic (right hemisphere) take on things. But even more was
involved. In order to utilize integration skills (which give us language
rules, hunting/aiming skills, social cohesion and other centralized
experiential phenomena) yet keep from experiencing flooding, required
what neurologist William Calvin has referred to as a “get-set” response.
(1990) This is essentially a pause function designed to hold inputs in
abeyance, brace the person prior to aiming, interpreting, interacting
socially or for that matter engaging in any behavior until response
refinement can occur. It is the precursor to what we now refer to as
attention span. In human evolution a bipedal movement style helped that
process along because having to shift from the left to right leg
(something our more centralized primate cousins cannot do) forced a
sequential behavioral and movement style. Thus upright walking required a
pause between alternating limbs so the left and right side would not be
activated simultaneously. The same sequential function within the brain
likely set the stage for step-by-step cognition, including language
grammar, logic, mathematical operations, analytical thought, extended
attention span and other cognitive skills.
.jpg)
