On Aug 27, 8:08 am, Sir Frederick fuzzysys.com> wrote:

Interesting article and strange that the religious right network would
put it on their page.

Every moment of consciousness includes not just sensation, but also a
reaction. Many people talk about the mind as if it were essentially a
passive display. Whipping up a state of subjective experience is what
counts. Yet the whole point about having a brain is to act. Evolution
has no use for an organ that just wants to sit and watch the world go
by, regardless of how rich or beautiful the flickering parade of
images might be. The job of a brain is to turn sensations into
behaviour.

So if we are looking for the needs that shape the brain's
organisation, then the need to form an intelligent reaction to the
moment must be the ultimate. And certainly, the importance of action
to the brain seems to be suggested by the simple fact that the entire
front half of the human cortex is devoted to it. Each cycle of
processing may begin with a journey up the flanks of the sensory
hierarchy, but it is not until the front half of the brain has taken
notice and decided 'Now what?' that a moment of consciousness can take
on real overtones of meaning and purpose.

As mentioned, the general organosation of the frontal cortex is like
the sensory cortex in reverse. Just like the sensory cortex, the
frontal cortex is a patchwork of mapping areas tied into a dynamic
hierarchy. But instead of processing beginning at the bottom with raw
patterns and then ascending to highly abstract representations, the
processing in the frontal cortex starts with an abstract level of
mapping in the prefrontal lobes and then washes down through a series
of mid-level motor filters until it hits the primary motor area. An
inkling of what ought to be done gets turned into a mapping of actual
muscle commands by a process of decomposition.

Between the prefrontal planning zone and the primary motor output map
stand two main rungs of mapping, the supplementary motor area (SMA)
and the premotor area. Experiments have revealed that, broadly
speaking, the supplementary motor area takes the prefrontal's urge to
do something and creates a plan. It holds memories of what kind of
motor acts suit what kinds of occasions. The premotor area deals more
with the nitty-gritty detail of coordinating a movement. In scanning
studies, when subjects simply thought about making a finger movement,
only the SMA lit up, but when they actually went ahead and made the
movement, the premotor and the rest of the motor hierarchy began to
fire. This division of labour is supported by the connections the two
regions have to other parts of the brain. The supplementary motor area
is linked to the sensory hierarchy, making it well placed to generate
planning imagery. The premotor cortex also talks to the sensory
hierarchy, but at a much lower level, connecting mainly to body-
centred maps of nearby space.

It is a tempting idea to think of the SMA and premotor cortex as
'commanding' a muscle movement. The simple story would be that the two
areas plan an action, then pull on the strings of a topographical
mapping in the primary motor cortex to jerk the body's muscles into
action. But as we saw from the evidence of sports psychology and ERP
recordings, the explanation is far more complicated. Conscious-level
thinking is too slow to control an action as it is happening. So while
the cortex areas might help prepare the plan in advance, the fine
detail and late adjustments would have to be left in the hands of a
network of evolutionarily more primitive motor centres, including the
brain stem, the spinal column, the basal ganglia, and the specialist
bulge on the back of the brain stem, the cerebellum.

The cerebellum, in particular, picks up an action plan in the final
few hundred milliseconds and uses a host of subconscious habits to
smooth its execution. It is the cerebellum that does things like
tighten a muscle at the precise moment needed to start applying a
brake to our arm as we reach to the back of a cupboard, or judging
when we have a tight enough grip on a bag to begin lifting it up. The
ponderous planning of the motor cortex and nimble adjustments of the
cerebellum meet up on M1, the primary motor cortex map. As said, like
the somatosensory cortex next to it, the primary motor cortex is
organised as a topographical mapping of the body with the feet
represented at the top end, hands in the middle, and then head at the
bottom. Cells in M1 get input from both the cortex planning areas and
the cerebellum, so stand at the end of the line for a steadily
sharpening set of commands as the time for making a movement arrives.
There will be a dynamic gradient which starts with a general
anticipatory warning of the kind of action that might be needed in
half a second's time, running down to the delicate, last instant
adjustments organised by the cerebellum.

The generation of a motor act has a simple, self-assembling logic.
During the first half of a processing cycle, the brain extracts a
focus from the moment. An event or thought is promoted to the highest
levels of mapping. This focus then feeds a top-down cascade of
activation. In sensory areas, the top-down flow creates associations,
images, and states of priming, but in the motor hierarchy, an instant
of focus will automatically be decomposed to form a detailed action
plan. Noticing a neglected cup of coffee will put us in mind of taking
a sip; hearing our grandmother's voice would turn our feet in the
direction of the living room rather than the kitchen, where we were
originally headed. We cannot help pay attention to some fact or
occurrence without beginning to think about the inherent possibilities
for action - what the psychologist James Gibson dubbed a situation's
'affordances'.

Not surprisingly, generating thoughts about action and manipulation
takes up a large chunk of the frontal cortex sheet...

Going Inside - A Tour Round a Single Moment of Consciousness
John McCrone - 1999
http://www.amazon.com/exec/obidos/tg/detail/-/0880642629/qid=1085586459/
http://www.dichotomistic.com/readings_intro.html

Well, gotta turn that on its head man, use the very science they are
using to put it back, you know since if, the environment that molded
the human brain through natural selection is drastically different
than the world humans currently live in and his disparity between what
man was designed to do and what he currently can do leads to a host of
societal difficulties; including false categories and stereotypes to
try and label some with peculiar abilities as "mental?"

The Savanna Principle is a theory about the evolutionary roots of the
human brain. ...it asserts that the environment that molded the human
brain through natural selection is drastically different than the
world humans currently live in. This disparity between what man was
designed to do and what he currently can do leads to a host of
societal difficulties, according to the theory. For example, ancestors
who craved sugary and fatty foods lived longer and were healthier than
those who didn't, in a time that such things were relatively scarce.
Today, the abundance of such temptations leads to obesity and heart
disease.

http://en.wikipedia.org/wiki/Savanna_principle