Biology Reference
In-Depth Information
Output Signal from Brain = Fast
Metastable Neural
Oscillations (Assembly &
Disassembly) = Slow
All possible neural
assemblies are
constantly being
formed and destroyed
Input Signal to Brain = Fast
When the “right”
neural assembly is
formed, it can
couple the two fast
process
In order to couple these two
processes you need to have a
metastable process
Postulation how metastable state couples
the fast neural processes in the Brain
Fig. 15.21 The generalized Franck-Condon principle postulated to underlie the coupling between
(1)
the cortical column assembling/disassembling
process essential for mental activities, and (2)
synchronous firings of muscle cells
during the micro-macro coupling accompanying body
motions. See text for details (
I thank Julie Bianchini for drawing this figure in December 2008
)
postsynaptic targets in their neighborhood by undergoing random fluctuations
or Brownian motions
, just as molecules undergo Brownian motions or thermal
fluctuations until they find their binding sites. But the “seemingly” random motions
postulated to be executed by axon terminals are active (in the sense that depolarized
axon terminals are thought to be unable to undergo such explorative motions),
while the random motions of molecules are passive since no free energy dissipation
is involved. We will therefore refer to the seemingly random motions of axon
terminals as “actively random,” “quasi-random,” or “quasi-Brownian” and
the conventional Brownian motions of molecules as “passively random,” “truly
random,” or just “random”. Quasi-random processes may be slower than truly
random processes.
As indicated above, there are approximately 10
6
cortical columns in the motor
cortex per hemisphere (Cook 1986, p. 63). These motor columns may undergo
quasi-random interactions
, exploring all possible patterns of interactions or
configurations, and when the right configuration is selected or stabilized by input
signal to the brain, that particular set of motor cortical columns is thought to be
activated (or depolarized), leading to an almost simultaneous activation of their
target muscle cells which results in visual input-specific body motions. This series
of postulated events are schematically represented in Fig.
15.21
. Using the language
