🚀 go-pugleaf

It's been pointed out that neuropil functions as a four-dimensional 
manifold of signature (+,+,-,-). Bob Shaw and his coauthors discuss this 
in Robert Shaw, Endre Kadar, and Jeffrey Kinsella-Shaw, "Modelling 
Systems with Intentional Dynamics: a Lesson from Quantum Mechanics," in 
Pribram, K., ed., Origins: Brain and Self-Organization, INNS Press and 
LEA, 1994. The basic argument seems to go as follows: 

Principal neurons of the cortex function as coincidence detectors. 
This (simplified) means that a two-dimensional patch of neurons is in the 
past of two other patches and (by symmetry) in the future of yet two 
other patches. In spiking or not spiking, the neurons of the local patch 
act independently, but based on a output of a shared dendritic arbor and 
with parallel outputs. This results in a 4-dimensional topology with two 
space-like dimensions and two time-like dimensions.

Shaw, et al., use this argument primarily to address intentional 
dynamics, which is associated with the observation that every point in 
the near space of an individual is associated with two fields--an 
intentional (semantic) field and an operational (behavioral) field. 
Mishkin's lab has evidence that cognitive and behavioral memory are 
independent systems, which suggests that Shaw's model is real.

This two-field representation of space seems to quite primitive. 
Heterokont zoospores (protoctists) have two undulipoda (flagella), a
mastigoneme (hairy undulipod) that is sensory and a smooth undulipod that
is motor. Associated with each point in near space is a semantic component
("tastes good") and a motor program ("how to get there"). Cognition in
protoctists seems to involve a data transfer from the mastigoneme to the
smooth undulipod. In advanced protoctists with eyespots (Euglena and the
eustigs), the mastigoneme seems to have become reduced, but it still
connects the eyespot to the smooth undulipod. 

Does this matter? Possibly. Although animal sperm have only a smooth
undulipod, animal sensory cells (hair cells, olfactory cells, visual
receptors) appear to use a modified mastigoneme for sensory transduction.
That suggests the dendritic arbor of generalized neurons is a modified
mastigoneme and the axon is a modified smooth undulipod. It also suggests
the cognitive/behavioral dichotomy is extremely primitive... 

Cheers,
--
Harry Erwin
Internet: herwin@gmu.edu