Biology Reference
In-Depth Information
coordination dynamics
(Bernstein 1967, Kelso 1995, Turvey and Carello 1996,
Jirsa and Kelso 2004, Kelso and EnstrØm 2006)
.
When two objects A and B are coordinated via SCM, they are connected to a
rigid body C so that A, B, and C form a mechanically coupled
simple machine
(to be
called the
SCM machine
) and the movements of A and B are automatically coordi-
nated. But when A and B are coordinated via DCM, they are connected to a
deformable body C (to form what may be called the
DCM machine
) in such a
manner that A, B, and C are mechanically coupled system only when appropriate
conditions are met. In other words,
the DCM machine is a much more complex and
sophisticated than the SCM machine. In addition, the DCM machine is synonymous
The First Law of Coordination Dynamics (FLCD), Statement 15.36, is a
phenomenological law similar to the laws of thermodynamics and does not provide
any detailed mechanism as to how the law may be implemented in real life. To
the extent that empirical data can be marshaled to formulate realistic mechanisms
to implement FLCD, to that extent FLCD will gain legitimacy as a law. Figure
15.17
provides an empirically based mechanistic framework for implementing FLCD and
hence can be viewed as a diagrammatic representation of FLCD. According to
Fig.
15.17
, FLCD consists of two causes - upward causes or mechanisms (Steps 3
and 4) and downward causes or mechanisms (Steps 1 and 2).
The
upward mechanisms
implementing FLCD implicate the hierarchical orga-
nization of material components of the muscle from the myosin molecule to the
muscle attached to a bone, ranging in linear dimensions from 10
10
to 1 m (see
Fig.
15.19
). Figure
15.19
exposes the essential problem underlying the upward
mechanism:
How can myosin molecules move the muscle?
For example, in order for
our arm to move a cup of tea or an apple, the arm muscle must generate forces in the
range of 1 N acting over distances in the range of 1 m in less than 1 s (Fig.
15.19
).
But a myosin molecule can generate forces only in the range of 1 pN (picoNewton,
or 10
12
N) acting over distances in the range of 10
8
m. That is,
In order for our body to move an object powered by chemical reactions, our body must
(i) amplify the forces generated by individual myosin molecules from 10
12
Nto1N
(an increase by a factor of about 10
12
), (ii) extend the active distance of the molecular force
from 10
8
m to 1 m (an increase by a factor of about 10
8
), and (iii) slow down processes
from 10
9
s to about 1 s (a factor of about 10
9
). (15.37)
We may refer to Statement 15.37 as
the FDT amplification requirement
(FDTAR) for the micro-macro coupling in the human body, F, D, and T standing
for
force
,
distance
, and
time
, respectively. Now the all-important question from the
perspective of coordination dynamics is:
How is the FDTA requirement met in the human body?
(15.38)
As a possible answer to Question 15.38, it is here suggested that there are two
key principles to effectuate the FDT amplification in the human body:
