MAJOR THEMES OF THIS WORK
PROCESSES IN BIOLOGICAL VISION
Last Update 02 July 09
Rhodonine™ and Activa™: See Citation Page
This work differs fundamentally from the conventional wisdom concerning Vision.
Many of these variances are summarized on this page.
The most important differences are summarized in the following sections:
- the major differences are listed as six PARADIGM SHIFTS
- these differences lead to a longer list of the BASIC PREMISES
that have evolved following the development of the paradigm shifts.
- a long list is also included in the subsequent section,
FUNDAMENTAL CONCLUSIONS
.
- a brief summary of the findings relative to the organization of the BRAIN, both mid-brain and cortex, appear next.
- The above summary leads to a group of new findings concerning the functional operation of the brain, as in READING.
PARADIGM SHIFTS SUPPORTING THE THEORY
One of the primary reasons for preparing this text, which grew beyond all
expectations, was to provide a sufficiently broad base to successfully challenge
the conventional wisdom that photoexcitation in vision involved the process of
isomerization. As described, that process has always required energy from a
distinct source separate from the incident photons. There was another mechanism
that was clearly more appropriate.
There was a similar problem in the area of how the above photoexcitation process
led to an electrical signal within the neural system. Exploration led to a rational
solution to this problem. That explanation led to a more complete understanding
of how the generated signal was transmitted to the brain, etc.
The following basic principles were defined based on the available laboratory
investigations. They are in blatant conflict with the conventional wisdom. However,
they do provide the most comprehensive explanation of any available theory of
vision. This explanation extends to levels of detail that are not even
discussed in alternate theories.
It is hoped that these basic principles can be kept in mind as the reader
explores this site and the printed text. It is hoped that the reader will
discern the value of these proposals when he/she examines the added insights
they provide into the visual system in man and other animals.
I. Vision is basically tetrachromatic, not trichromatic
An astounding finding of this investigation was the fact that the basic architecture of biological vision is tetrachromatic. In the fully developed visual system, four chromophores are used to support four spectral channels. These channels are in the ultraviolet, blue, green and red. There has been a growing awareness for some time that many chordates exhibited tetrachromatic vision. During the last quarter of the 20th Century, it was shown that the retina and later parts of the human visual system are tetrachromatically organized. The human visual system is limited by the lens group of the eye. This property is shared with other large animals. As a result, these animals are fundamentally blocked tetrachromats instead of trichromats. This fact is important when exploring the short wavelength capabilities of the visual system (and when attempting to correlate genetic code to vision).
II. Rhodonine instead of Rhodopsin
The experimental literature is now conclusive that rhodopsin is not formed within the
photoreceptor cells. The photoreceptor cells are known to secrete opsin that is
then extruded to form the disks found in the Outer Segment associated with each cell.
The opsin is then coated with a chromophore in liquid crystalline form that is
created within the retinal pigment epithelium layer of the retina.
It is proposed that this liquid crystalline material, known as Rhodonine®,
is the chromophore of vision. This material is fabricated from retinol by a well
defined series of processes. Rhodonine is a close relative of the chromophores used
in color photography. It is excited by a quantum mechanical process exactly as
in color photography and is de-excited by a well known process (used commonly in
solid state transistors) occurring at the dendrites of the photoreceptor cell. No
external source of quantum level energy is required. This excitation/de-excitation
process precisely describes the "waveform generator" signal reported in the literature.
Rhodonine is found in four varieties, all of which are used in vision. Using
the proper technique, any one of the four variants of the material can be
extracted from a retina and reconstituted in the laboratory. (This
experimental sequence has never been performed with the putative rhodopsin)[5.5].
The recovered material exhibits precisely, and without difficulty, one of the
four spectrums found in vision. The actual operational spectrum of the
putative rhodopsin has never been recorded in-vitro in the laboratory.
III. The neuron as an electrolytic semiconductor device
Conventional wisdom since the 1950's has been that the axolemma of the neuron,
a simple bilayer film of liquid crystalline triglyceride material, is an
active two terminal device. There has been no explanation of why it is active. As
an alternative explanation, it is proposed that when two such bilayer films are
brought into close proximity, the resulting structure can form a three terminal
electrolytic semiconductor device, known as an Activa®. This device acts
like a conventional solid-state semiconductor device. The Activa is an electrolytic,
(organic) semiconductor device, US Patent #5,946,185. Such a device
can be found at every junction between two plasmolemmas in the nervous system.
The three terminal Activa is the fundamental building block of the nervous
system and accounts for the detailed performance of the synapses, the
Nodes of Ranvier, and both the de-excitation of the chromophores
of vision and the adaptation process. [8]
IV. Replacement of the constant field equation of Goldman
With the introduction of semiconductor theory to explain the fundamental
character of the biological membrane at the molecular level, the constant field
theory that has evolved based on Nernst, Donnan & Goldman is found to be
inadequate. The potential barrier found within the relative portions of the
plasma membrane of a neuron introduces a variation in the potential field
within the membrane that profoundly impacts the permeability of that membrane.
The state of a neural conduit is best explained by a new variable field theory.
V. The eye as a change detector, not an imager
Because of conceptual simplicity, conventional pedagogy teaches that the eye is
an analog of the simple box camera (with a simple lens system) and the retina acts
like a piece of photographic film. Unfortunately, the overwhelming evidence that
the eye is not an imaging device is not introduced at higher levels in the
educational system. Volumes have been written on the fact that the human eye is
blind in the absence of motion between the optical line of sight and the scene.
This motion is normally provided by the tremor associated with the ocular globe
of the eye.
It is proposed that the photoreceptor cell is a change detector and not an
imaging element. Recognition of this well documented situation leads
to a detailed explanation of the adaptation process and color constancy,
as well as many special optical illusions.
Vi. The specific definition of color at the fundamental level
In the absence of a precise definition of color in the conventional wisdom, a paradigm
shift may be an inappropriate description for this section. However, it is
necessary to define a color uniquely from a conceptual, scientific and practical
perspective.
A perceived color for a long wavelength trichromat is defined precisely by the
pair of values, (P,Q), associated with the two chrominance channels of animal vision. These are best visuallized via the New Chromaticity Diagram for Research. This Diagram demonstrates the bilateral orthogonality of the visual system, a P-channel and a Q-channel, as opposed to the long assumed trilateral symmetry, RGB or xyz, of the system.
The individual is taught, within his cultural and semantic environment, to
associate a name to each set of perceived P,Q values. The values describe the
precise color perceived. The semantic name is that used to report the perception
of that color by the individual.
Based on the above definition, the precise definition of white is also available.
"White is the reported color, of a light or an illuminated surface,
perceived by an animal when each and all of the chrominance channels of its
visual system are reporting a null condition to the cortex for that incident
illumination. For a long wavelength trichromat, this condition corresponds to a
null in both of the chrominance channels, P:Q::0:0"
The above definition leads to one additional definition required to avoid
controversy. For completeness, it has been divided into two variants.
Neglecting the effect of the illumination for a moment.
Any two surfaces that cause the same (P,Q) values to be perceived
and interpreted by the cortex when illuminated by the same source, are defined
as metamers in object color space.
For completeness, a broader definition can also be given.
Any two surfaces that cause the same (P,Q) values to be perceived
and interpreted by the cortex when illuminated by different sources, are defined
as trans-metamers in object color space.
PREMISES DEVELOPED IN THIS WORK
To aid in understanding this work, it is useful to provide a roadmap of the premises
developed within it. It is only by comprehending these premises as a group that
the overall work can be considered and the scope of the entire work can be appreciated.
An attempt will be made to list these premises in a quasi hierarchal manner beginning
in object space and proceeding toward the cortex. However, the system deviates
substantially from a single topological signaling path, or even parallel
topological paths. The bold roman numerals, e.g. (II), at the start of a subject indicates it is directly
related to the above section on PARADIGM SHIFTS
These premises were developed in conjunction with the development of the various
block and circuit diagrams of vision and are based on the data in the literature. The
premises are confirmed by the ability of a new set of performance descriptors to
define the performance of the visual system with a precision not found elsewhere. All
of these performance descriptors can be filtered to emulate the performance
previously measured in the laboratory with less than adequate instrumentation or
experimental design. Many of these premises can be confirmed by the reader, in an anecdotal
manner, using the simple tests defined at this web site.
Basic Premises
- A phylogenic tree of the animal kingdom can be presented that allows the
visual system of Arthropoda, Mollusca and Chordata to be traced back to
a common ancestor.
- This common ancestor appears to be one of the earliest bilateral flat worms.
- The existance of this common ancestor is strong support for the fact that
all animal visual systems employ the same functional topology and mechanisms,
while implementing that topology and those mechanisms through a variety of
morphological techniques and adaptations.
- A frequent claim that insects employ a different signal topology than
the chordates arose through a misinterpretation and/or assumption relative to the
data of one experimenter. He did not play an active role in the resulting discussions.
Subsequent data shows that his data was correct but his model, and that of the
other analysts, was inadequate.
- The error was based on the assumption that the photoreceptor cell was a
two terminal device. In fact, it is a three signal terminal device. Counting the
additional power supply connections, it has even more distinct terminals.
- The thickness of the physiological optical system forward of the retina plays
a major role in determining the spectral capability of an animal.
- The absorption in the ultraviolet region of the material distal of the
retina is relatively high.
- The thickness of this material generally increases
with animal size.
- If due to no other cause, many animals lose their ultraviolet
vision with growth and maturation.
- The thickness increases drastically when an animal, of a given size,
moves from the marine environment to the terrestrial environment and must
compensate for the difference in the optical index of refraction of air versus water.
- a variety of amphibious animals, including diving birds, incorporate
alternative or switchable optical systems in order to accomodate this difference.
- Man exhibits a rudimentary nictating lens left over from his transition from
the aquatic environment.
- The photoreceptors of vision are quantum, as opposed to energy, detectors.
- The performance of the photodetectors are describable using Fermi-Dirac statistics.
- The absorption spectrum of each spectral class of photoreceptors is
calculatable with precision.
- Photoexcitation and de-excitation are quantum mechanical processes
- The complete photoexcitation/de-excitation process can be described
by a single differential equation with fixed coefficients,the P/D Equation.
- This equation describes the initial waveform generator equation as
measured in the Interphotoreceptor matrix (IPM).
- (I) Spectral absorption is accomplished in the Rhodonines, a resonant form of the
retinoids while they are in the liquid crystalline state.
- These retinoids are derived from retinol, are members of the indicator family
of retinoids, and each molecule contains two auxochromes (presumed to be oxygen).
- The length of the conjugated carbon chain between the two auxochromes
determines the spectral characteristics of the molecule when in the liquid crystalline
state.
- Neither the auxochromes or the overall Rhodonine molecules are chemically
bonded to any protein.
- The Rhodonine molecules are deposited onto a substrate, putatively opsin, as
a liquid crystalline structure. The liquid crystalline material is attached to
the substrate only by hydrogen bonding.
- There are four Rhodonines that provide the appropriate spectral absorption
in the ultra-violet, short, medium and long wavelength regions of the visual
spectrum.
- The absorption parameters of the Rhodonine exhibit a nominally equal
spectral spacing with respect to wavelength. However, their properties are expressed
via Fermi-Dirac statistics which do not define a "peak wavelength." As a result,
the individual spectrums exhibit a different quality factor, or Q, and a nominal peak
wavelength obtained graphically after plotting their individual long and short
wavelength absorption characteristics.
- The Rhodonines only exhibit their unique absorption characteristics when in the
planar liquid crystalline state.
- In the planar liquid crystalline state, the Rhodonines exhibit two independent
absorption spectrums, one isotropic and one anisotropic.
- The anisotropic absorption coefficient is much higher than that of the
isotropic coefficient.
- The anisotropic absorption coefficient is maximum for light with a Poynting Vector
perpendicular to the plane of the planar liquid crystal (the light impinges at a
right angle to the surface of the crystal).
- The suction pipette technique provides an excellent method of demonstrating
the anisotropic and isotropic absorption spectrums of the same in-vivo Outer
Segment.
- No data exists in the literature demonstrating the appropriate spectral
absorption of any material based on the chemical retinol combined chemically with
another biological chemical found in-vivo, unless it does so in such a way as to
preserve the dual auxochrome configuration found in the Rhodonines.
- The Outer Segment of a photoreceptor cell is NOT an integral part of the cell
- The Outer Segment is an extra-cellular structure formed by the secretion
of a strip of the protein opsin.
- The strip of opsin is folded and broken to form a stack of individual pieces.
- The stack of individual pieces is then extruded into the IPM space by the
distal cup of the photoreceptor cell.
- The extrusion die forms the furrows along the side of the stack into which
the dendrites (generally known as microtubules in morphology) of the
photoreceptor cell are deposited.
-
Although this premise is not crucial to the theory presented here, it is
crucial to the viability of several alternate theories.
- The calcium gate and glutamate cascade theories both require a membrane,
which includes "gates," surround the Outer Segment
- The putative membrane of these theories is derived from a pair of caricatures
presented in the late 1960's.
- There is no electronmicroscopic evidence in the literature demonstrating the
existance of a membrane surrounding the Outer Segment in the region between the
end of the extrusion cup of the photoreceptor cell and the beginning of the
phagocytosis cup of the RPE cells.
- To emphasize the importance of the above fact, VISION CONCEPTS is offering
a CASH REWARD to anyone who can provide definitive
evidence of the existance of such a membrane.
- There are a number of difficulties with the membrane assumption.
- It becomes difficult to explain how the RPE is able to phagocytize an
integral part of a living cell without destroying the viability of that cell.
- In electronmicrographs of cleaved Outer Segments, there is no suggestion of
any debris associated with an external membrane.
- A large number of Outer Segments are cleaved when the neural structure of the
retina is torn from the RPE layer. This condition is not associated with the death
of a large number, or any number, of photoreceptor cells. Although removed from
the normal focal plane of the optical system, the photoreceptor cells are known to
remain viable sensory elements.
- Translation of the signal from the disks of the Outer Segment to the dendrites
of the photoreceptor neuron is a piezo-electric process.
- The process is energy sensitive and accounts for the unique performance
of the long wavelength spectral channel, the L-channel.
- (II) The fundamental neural mechanism involves an active electrolytic semiconductor
device, the Activa,
- The Activa is a more fundamental unit than the neuron.
- Many neurons incorporate more than one Activa.
- Each Node of Ranvier is the site of an Activa within a neuron.
- The synapse between two neurons is the site of one or more Activa.
- Many synapses employ an array of individual Activa in order to achieve
greater power handling capability, just as in man-made transistor devices.
- The Activa exhibits "transistor action" identical to that in a man-made
transistor.
- The Activa can provide signal amplification.
- The Activa can provide internal negative feedback.
- The neural system is fundamentally electrolytic in operation.
- The electrical power to support the neural system is provided by an
electrostenolytic process based on a glutamate energy cycle.
- It is the general need for the glutamate cycle components at the surface
of every neuron that accounts for their wide distribution in the body and the
concentration of that distribution along the surface of the neural pathways.
- The electrical power supply to the retina is limited by the rate of
perfusion of the necessary glutamate cycle components within the layers of the retina.
- This limitation introduces a fundamental limitation on the signal
performance of the retina described as adaptation.
- There is no functional equivalent of the morphological distinction, "rods and
cones," in the animal visual system
- all mature photoreceptor cells of vision exhibit similar functional performance.
- All photoreceptors are operational over the entire range of radiant
ntensity found in the natural environment.
- There are no "broadband" photoreceptor cells in animal vision. All
photoreceptor cells exhibit one of four narrow band spectral responses dependent
on the particular Rhodonine molecule coating the disks of its Outer Segment.
- The method of disk formation and continual disk transport across the IPM
preclude a cone shaped structure associated with the Outer Segment of a mature
photoreceptor cell.
- The first of two Activa within each photoreceptor cell is used to form the
adaptation amplifier of each spectral absorption channel.
- This Activa operates in a complex circuit that determines both the adaptation
and color constancy characteristics of the visual system.
- The Activa of the adaptation amplifier is arranged in a common emitter
configuration (within a differential pair configuration to be discussed below).
- This configuration introduces a high degree of negative internal feedback
into the circuits performance
- This negative internal feedback establishes the constant average amplitude
signal environment at the emitter (output terminal) of the adaptation amplifier.
- The bleaching of the chromophore material and its reconstitution under the control of the current supply of the adaptation amplifier is the source of adaptation in vision.
- The bleaching of the chromophore material is the principle mechanism of adaptation.
- This mechanism, when shared by adjacent detectors determines the
transient adaptation characteristic of vision.
- This mechanism when not shared with adjacent spectral channels determines the
"color constancy" characteristic of vision.
- The transient performance of the adaptation amplifiers is due to both the
excitation (bleaching) of the chromophore material and the limited metabolic supply phenomena.
- The light and dark adaptation functions are fundamentally different because
of the nature of the Activa at the heart of the circuit.
- The dark adaptation function is described by a 2nd order differential
equation with variable coefficients.
- The solution of this differential equation is a sinewave modulated exponential
function of time.
- (III) In order to accomodate the extreme range of radiant intensity in the
natural environment within the limited dynamic range of the perceptual signaling
channels, the adaptation amplifier effectively removes the average component of
the signal representing the radiation incident on a given photoreceptor cell.
- In the absence of a change in radiant intensity projected onto a photoreceptor
cell as a function of time, the visual systems of all animals are blind.
- This fact is easily demonstrated in any optometrists office using the
visual field measuring set to generate a uniformly illuminated scene without a
border or contrast edges within the field of view.
- In the absence of additional mechanisms, the majority of the species in the
animal kingdom are blind in the absence of moving objects within their field of
vision.
- The higher members of both the Chordata and Mollusca phyla
have developed mechanisms to overcome this limitation of the fundamental
visual system.
- In Chordata, the eye has evolved to have a certain degree of rotational
freedom. By introducing a small but rapid oscillatory rotary movement of the
eye, called tremor, the system has introduced a discontinuous but essentially constant
motion between the optical line of site and the scene.
- This continual motion has a profound impact on the signal processing
methodology in these animals. The majority of the signal processing occurs in
the temporal domain that has been largely overlooked by the electrophysiologists.
- In Mollusca the higher animals have evolved a certain degree of
torsional freedom between the eye and the body of the animal. By introducing
a small but rapid oscillatory torsional movement of the eye, which can also be
described as tremor, the system has introduced a discontinuous but essentially constant
motion between the optical line of site and the scene.
- The tremor mechanism is under voluntary neurological control in some
animals within Chordata.
- Some members of both Phyla have learned to introduce motion between the visual
line of sight and the scene in object space by moving their head or other
body elements.
- The second Activa found within each photoreceptor cell operates as a grounded
base amplifier with an input terminal, emitter, connected with the emitter of the
adaptation amplifier within the same cell.
- This circuit acts as a low impedance distribution amplifier with a
current gain of between .99 and 1.00
- The impedance in the collector, or output subcircuit, of this circuit
consists of an axon membrane acting as a diode.
- This output impedance causes the voltage at the pedicel of the cell
to be a "natural" logarithmic representation of the current through the
impedance (axolemma).
- In the low, but finite frequency, signaling mode, this voltage is a
logarithmic representation of the applied irradiance in object space with the
characteristic of the logarithm expressing that irradiance level reduced by the
action of the adaptation amplifier.
- In the transient mode, this voltage is described as the waveform generator in most of the
literature. It is distinctly different from the "waveform generator measured in
the IPM space."
- Following logarithmic conversion at the pedicels of the photoreceptor cells,
separate signaling matrices are created using lateral cells to create the
primary perceptual signals used in the visual process. These matrices are of two types,
those using horizontal cells to create the luminance, chrominance, and polarization
signals and those using amercine cells to create the appearance signals.
- A luminance matrix provides a summation signal in perceptual
space (The sum of the "adjusted" logarithms of the radiant intensity applied to
each spectrally distinct photoreceptor channel.
- A chrominance matrix provides a difference signal in perceptual space between
each pair of spectrally distinct photoreceptor channels. (The difference of the
"adjusted" logarithms of the radiant intensity applied to each spectrally
distinct photoreceptor channel.
- The resulting multiple signals can be considered
to represent the ratios between the individual chromatic signals. However, this
interpretation will lead nowhere. It is the difference expressed as a voltage that
is processed in the visual system.
- The system is deterministic. Only one of the possible two signals formed by
taking the difference between two signals is used. The pair used in long wavelength
trichromatic vision appear to be P = LnS - LnM and Q = LnM - LnL
- An Additional matrix provides a difference signal in perceptual space between
each pair of certain spectral classes of photoreceptors arranged orthogonally in
object space to provide a polarization sensitive signal. (The difference of the
"adjusted" logarithms of the radiant intensity applied to each polarization
distinct photoreceptor channel.)
- An additional matrix is found in the retina that involves the amercine cells.
It is used primarily to process signals representing spatial characteristics of the
scene in object space.
- Although used to process spatial information, the amercine cells process
this information primarily in the time domain. The arrangement of their dendritic
arborizations is designed to facilitate temporal processing at the location of
the Activa within the amercine neuron.
- The signal processing related to the photoreceptor cells of the foveola is
fundamentally different from the ex-foveola cells. These signals are treated
uniquely.
- The foveola signals are directed to the pretectum of the mid-brain.
- These signals are processed for two purposes:
- To extract precision spatial information that is sent to the cortex where
they enter via Area 7.
- To extract error signals in cooperation with the rest of the precision optical
system (previously known as the auxiliary optical system)to control the line of
sight of the eye via the oculomotor system.
- The ex-foveola signals are directed to the lateral geniculate nuclei (LGN)of the
mid-brain.
- Within the LGN, the signals are processed to extract both stereoptic and
alarm signals.
- The stereoptic signals are actually processed in the time domain, not the
spatial domain. The signals are expressed in the time domain when they arrive at
the LGN due to the variable length of the optic nerves connecting to the ganglion
cells of the retina. The arrangement of the neural paths in the retina mirror the
arrangement of the optic nerves leaving the LGN in the region known as Henry's
Loops.
- The signals from the LGN are passed to the cortex primarily entering the cortex
via area 17.
- As seen above, the designation of this area as the "primary visual
cortex," particularly in the higher primates, is probably inappropriate. The most
important visual signals, in at least the higher chordates, do not enter the
cortex through this route.
- The employment of separate luminance and chrominance signaling channels,
employing distinctly different mathematical manipulations, is not compatible
with a "linear vision model" except under the most restrictive small signal
conditions. In addition, it is clear that the chrominance signaling channels
of vision do not employ "additive color" principles.
- The nature of the luminous efficiency function of vision differs
fundamentally from the empirical C.I.E. assumption.
- When measured with a sufficiently narrow band spectroradiometer, the actual
luminous efficiency function exhibits the features relating to the
Brezold-Brucke and the Purkinje effects. Only when smoothed does the function
take on the shape proposed by the C.I.E (or, depending on the width of the filters
and the color temperature of the illumination source, the alternate shape proposed by
Judd.
- The nature of the chromaticity functions differ fundamentally from the empirical
C.I.E. assumption, even after all of the empirical attempts (using arbitrary curve
fitting, frequently with discontinuous functions as in the case of CIELAB
and CIELUV) to provide a uniform chromaticity space.
- The actual chromaticity function can be presented in a uniform orthogonal
two dimensional color space as done in the New Chromaticity Diagram for Research
of this work (see Performance Descriptors on the Navigation Bar).
- A simple summation type color equation of the form R = X + Y + Z is not appropriate
for describing color vision in humans or animals.
- There is no simple relationship between luminance and chromaticity in
the perceptual space or in object space when refered from perceptual space,
when based on the visual system of animals.
- Use of spherical coordinates in perceptual (or object) space in an attempt
to define a visual solid is not theoretically defendable.
- The description of a multi-dimensional sensation space of vision as a color
space is poor practice, particularly since the majority of chordate animals
are tetrachromats and many others are short wavelength trichromats whose vision
can not be well described by a single three dimensional sensation space.
- (IV) By plotting the relative value of the voltage representing
P and Q compared to their quiescent value in the visual system of the long
wavelength trichromats, it is possible to obtain a definitive New
Chromaticity Diagram for Research.
- If plotted using an orthogonal two dimensional space (Cartesian), the
resulting perceptual color space is also orthogonal.
- The resulting diagram presents "white" as a unique condition represented by
a complete lack of signals in the chrominance channels, P = Q = 0.00 or "null".
- If plotted using the chromatic transfer function between spectral wavelength
and P and Q individually, a definitive New Chromaticity Diagram for Research as
a function of wavelength is obtained.
- This diagram provides additional absolute reference points for the conditions
P = 0 and Q = 0.
- The condition P = 0 occurs at 494 ± 2 nm. The precise value is
defined as the narrow band spectral color Azure in this work.
- The condition Q = 0 occurs at 572 ± 2 nm. The precise value is defined
as the narrow band spectral color Yellow in this work.
- The signal projection system of chordates employs a very sophisticated
spatial and temporal encoding system to minimize the mechanical stiffness associated
with the optic nerve.
- The system is deterministic. Nearly, if not, all of the useful information
gleaned by the retina is delivered in unaltered form to the cortex, and where
necessary the precision optical system.
- Speaking of many-to-one encoding as a lossy signaling approach indicates
a lack of understanding of the fundamental encoding scheme.
- The system employs a "matched pair" of time dispersion filters,
mechanical topographic structures, to allow stereoptic and other spatial signals
to be processed in the time domain without disturbing the overall operation of
the system with respect to the cortex.
- One of these time dispersion filters is defined as Henry's Loops.
The other is unnamed and comprises the neural path associated with the
axons of the ganglion cells of the retina prior to their entry through the
Lamina Cribosa into the optic nerve.
- The vast majority of the neurons in a given animal are operated in the analog mode.
- Only the signal projection neurons operate in the pulse mode
(generating "Action Potentials")
- There are vastly more signal manipulation neurons in the peripheral
nervous system than signal projection neurons.
- There are vastly more signal sensing neurons than projection neurons.
- There are vastly more signal manipulation neurons in the central nervous system
than projection neurons.
- The fundamental mechanism displayed by a neuron is not the excitability of the
axolemma. It is the "excitability, i. e. transistor action" achieved at the
junction between two lemmas.
- The activity found at a junction between a neurolemma and an axon is
frequently found within a neuron near, but independent of, the soma.
- The activity found at a junction between an axolemma and a neurolemma is
generally associated with a synapse.
- The activity found at a Node of Ranvier is a hybrid situation. It is formed
as the result of a conduit acting as an axolemma at its input (distal in the
case of a sensory system neuron)end and a neurolemma at its output end. The structure
is frequently described as an interaxon. The result is two conduits forming a
junction (resulting in the creation of an Activa).
- The so-called voltage clamp configuration has not been well characterized in
the past. The circuit diagrams of this work, reachable from the Navigation Bar,
illustrate at least five fundamentally different operating states obtainable
by implementing the standard voltage clamp protocol.
- The actual axolemma of the subject neuron, unencumbered by ancillary
electrostenolytic processes is a passive element in these experiments (as
befits its simple biochemical structure).
- The absolute steady state voltages measured by the instrumentation in this
experiment are a function of the dendroplasm and the podaplasm of the Activa
associated with the axon under evaluation.
- If all of the dendrite related material, including the dendroplasm, is
successfully removed from the neuron under test, the steady state axoplasm
potential will remain fixed.
- Under this condition, the transient response of the voltage of the
axoplasm in response to a voltage pulse applied to the same axoplasm is
described by a complex but totally passive impedance network made up of only
capacitors and diodes (any resistive components present of biological origin
can be ignored).
- The above response is complicated by the fact that the instantaneous
resistivities of the diodes present are functions of the voltage on the
capacitors.
- The resulting response is similar to that obtained in parametric pumping
used in man-made microwave signal manipulation circuits.
- There are three fundamental types of electrolytic circuits within the
neural system
- There are highly specialized signal sensing neurons at the periphery of
the system which generally contain multiple Activa in unique circuit configurations.
- There are signal manipulation neurons found in both the peripheral and the
central nervous system which generally contain only one internal (three terminal)
Activa plus a large number of Activas associated with the terminals of their
arborization.
- There are signal projection neurons (typically called ganglion cells),
located in both the central and peripheral neural systems, that contain a
series of Activa located at each Node of Ranvier.
- The operation of the projection neurons of the neural system (such as the
ganglion cells of the retina) are poorly understood.
- The literature has not clarified the difference between the phase velocity
of neural signals along the conductors of the neurons, neurites and axons, and the
group velocity represented by the average signal velocity between two
topographically (morphologically) similar points separated by one or more
Nodes of Ranvier.
- Whereas the group velocity of a neural signal may be only 44 meters/second,
the typical phase velocity is 4400 meters/second (both at 37 Celsius).
- A large amount of time is lost in the signal regeneration process within the
Node of Ranvier.
- The Node of Ranvier operates as a signal regenerator, not a signal amplifier.
Although the output waveform of a Node of Ranvier appears similar to the output from the
Activa near the soma of a typical ganglion neuron, it is a fundamentally
independent electrical circuit with its own electrical parameters.
- The nominal time lost is the time between the time the input signal reaches a
critical amplitude threshold and the time the output signal reaches its peak value.
This time is typically 0.19 milliseconds.
- The literature has not clarified the high rate of signal manipulation possible
within the neural system
- While the signal regeneration function and the myelination of the axons
of the typical projection neuron limits its intrinsic signaling rate, these
conditions are not present in the typical analog signal manipulation neuron.
- With a distance between its input and output structures measured in microns
instead of millimeters, and no additonal capacitance designed to generate a low
impedance Action Potential, it is possible for signal manipulation neurons to
operate at clock rates on the order of a few microseconds instead of a tenths
of a millisecond.
- It is likely these rates are realized within individual signal
extraction and signal creation engines of the cortex as well as in some of the signal
manipulation matrices of the retina.
- If realized, these signaling rates would change the entire discussion concerning
the maximum data manipulation rates of a cortex designed for a high degree of parallel
signal processing.
- The literature has not yet defined the organizational architecture of the cortex,
at least of the primates.
- This work has demonstrated that that organization does not employ parallel
signal paths within the cortex.
- The signal paths within the cortex are clearly based on a star network, providing
a maximum degree of interconnection with a minimum overall average circuit delay.
- A star network architecture is compatible with the observed multiple entry
point geometry of the primate cortex.
- The neural system of animals achieves extremely high efficiency through the
use of completely reversable electrolytic and electrostenolytic processes,
the use of diodes as sources of resistivity, but not resistance, and operation
at very low current densities.
- The resulting system does not employ a Carnot Cycle and is exempt from
the limitations of the Second Law of Thermodynamics.
- Exemption does not imply overcoming or breaking the Second Law.
- The fact that the retina operates with the generation of negligible heat has
been experimentally verified in the literature.
- This reversability of the electrostenolytic processes involved accounts for
the remarkable, and previously unexplained, electrical efficiency of the cortex.
- The energy employed in the neural system is not dissipated as heat but
is obtained from and returned to a chemical state within the glutamate
metabolic cycle. Any inefficiency results in the disposal and replacement of
chemically changed material within the vascular, and ultimately limbic and
renal, systems.
- The effective reversable operation of the electrostenolytic processes on the surfaces
of the neurons does require the effective metabolic transport of the components
of the glutamate cycle between electrostenolytic sites.
- This transport requirement is a primary determinant of the topographic
organization of the Nodes of Ranvier and of the synapses between neurons.
- The topographic organization of the Nodes of Ranvier are essentially the
mirror image of the organization of the pedicels of the photoreceptor cells.
- There is considerable danger in attributing color defects in the visual
system to specific genetic factors due to the large variety of failure modes
within the visual system. It is very unlikely that all of the failure modes
relatable to a single clinical condition can be assigned to a malfunction of only
a single gene.
- The predominant form of color abnormality in human vison does not involve
failure in the chromophores, or even the photoreceptor cells of vision. Subjects
with this abnormality generally exhibit a conventional luminous efficiency
function, indicative of the normal operation of all three spectral detection and
translation channels.
FUNDAMENTAL CONCLUSIONS
I. Maxwell & Hering were both right
By examining the visual system, in sufficient electrophysiological detail, it
becomes clear that Maxwellian Theory plays a dominant role in the achromatic
operation and Hering Theory plays a dominant role in the chromatic operation of
the visual system. The development of a detailed model of the process shows that
the debate that has been running for over 100 years is based on apples and oranges.
Abney and later Grassman were wrong with respect to vision
The field of Photometry has developed based primarily on the assumption of
additive color mixing of lights. Only with the advent of color reproduction
via printing has subtractive color mixing through the use of pigments become
important. Abney and later Grassman codified the laws of additive color,
including the assumption of linearity, as they
apply to lights and used those properties to describe vision. By examining the
visual process, it becomes abundantly clear that the laws of vision are not
based on additive color mixing. The so-called Basic Equation of Photometry
does not apply to the perception of brightness. It applies only to the
luminosity of a scene.
II. Color, as a phenomena, can be defined rigorously
There is no widely recognized, detailed definition of color in the literature.
The reason appears related to the number of different situations where the phenomena
arises. By subdividing these situations into eight cases, a definition of the
phenomena of color can be given for each one. The most important cases involve
light emanating from a source, sometimes called aperture light, light reflected
from a surface, sometimes called, surface light, and the electrical signals resulting
from the detection of light by the photoreceptor cells, and known in this work
as perceived light. The perceived light is processed in two distinct signaling
channels, the luminance channel and the chrominance channel. The light in the
chromimance channel can be properly defined as perceived color.
The important fact is that the spectral properties of aperture light are
additive as a function of wavelength, the spectral changes brought about by
reflection or absorption by a non-radiative medium are subtractive as a function
of wavelength, and the spectral properties of perceived light are manifest in
two orthogonal bipolar voltages obtained by a discreet subtraction
process between pairs of signals of different spectral origin in the
photoreceptor cells.
Because of the subtractive nature of the perceived color signals, the fundamental
assumption concerning additive colorimetry and the entire C.I.E. structure of
Color Standards is inappropriate for precisely describing the visual process.
III. The New Chromaticity Diagram can be combined with the
Munsell Color System
By overlaying the Munsell Color System on the New Chromaticity Diagram for Research, it
is possible to assign unique absolute spectral wavelength components to any color sample
based on a New Combined Chromaticity Diagram. This three dimensional diagram is named
The Sensation Space of Human Vision.
It is possible to increase the precison and accuracy of the Munsell
System using this new Sensation Space as a tool. The samples must be observed under the illumination conditions specified in the
original Munsell protocols,which are the same as those called for by the ICSS-NBS
publication of 1955 (and reprined in 1976-77). These protocols call for daylight
illumination using a northern exposure (no direct solar illumination),
essentially corresponding to an equal quantum flux illuminant at 7053 Kelvin
as defined in this work. Within this work, this illuminant is defined as Illuminant F
or D70.
The above ICSS-NBS publication listed 267 specific color names to describe the
complete Munsell Color Space. There was no suggestion of a correlation between any
of these names and spectral wavelength. Using the above overlay method, specific
spectral attributes can be assigned to each of these names, subject to an agreement
on how to determine the centroid of the color space assigned a specific name.
This assignment method assigns the same spectral wavelengths to metamers since
the assignment is based on the median spectral content of the sample in each of two
spectral bands, as represented by the P and Q channels in perceptual space. If
desired, auxiliary spectral filters can be used to determine individual secondary
spectral wavelength designations for individual metamers.
FINDINGS RELATED TO THE NEURAL SYSTEM
I. The neural system is electolytically rather than chemically based.
The neural system consists of a series of electrolytic conduits separated by Activas, active electrolytic semiconductor devices similar to transistors.
The equilibrium laws of Nernst, Donnan, Goldman and Hodgkin & Huxley do not apply to neurons.
Based on the knowledge gained since the 1950's, it is clear that the biological bilayer membrane used to form the neural conduits is not permeable to ions. These membranes can be symmetrical at the molecular level in which case they are also impermeable to fundamental electrical charges. If they are asymmetrical at the molecular level, they remain impermeable to ions but are electrically asymmetrical and semiconductive to fundamental charged particles (electrons and holes).
The asymmetry of the biological bilayer membrane to electrons is clear proof of the existance of a variable electrical field within the membrane. Such a field is inconsistent with the fundamental assumption of a constant electrical field used in the derivation of the Nernst, Donnan, Goldman and Hodgkin & Huxley equilibrium equations.
II. The argument over a chemical versus electronic synapse is over
The vast majority, if not all, synapses are fundamentally electrolytic and contain an Activa.
The electrolytic hypothesis provides detailed answers to questions about the synapse. These same questions can not even be expressed under the chemical hypothesis.
FINDINGS RELATED TO THE CORTEX AND MID-BRAIN
Great strides are being made at this time in our understanding of the brain. Only
particularly relevant comments will be made here.
I. The organization of the brain is not linear or sequential
Literature of the late 20th Century has been showing the topology of the cortex
of the brain related to vision as essentially linear or consisting of two parallel
linear paths with crossover connections. In both cases, entry to the visual part
of the brain was via the "primary visual cortex," labeled V1. This is inappropriate.
Entry points
There are two primary entry points to the cortex for visual signals. Signals
from the lateral geniculate nuclei of the thalmus enter the cortex via the
"coarse imagery" visual center, labeled V1 or area 17.
Signals from the Precision Optical System associated with the tectum enter the
cortex via the precision imagery visual center, located within area 7.
Organization
The cortex consists of an essentially two dimensional laminate of about six
layers in thickness. Each small region of the two dimensional surface consists
of functional sites defined as engines in this work. These engines are interconnected
in a n-pointed star configuration that allows efficient interconnection between
any two nodes of the star network. The engines associated with a given function
tend to be located within a specific area. The location and inter-relation of
the various areas appears to have been chosen on architectural and signal handling grounds.
II. The signal processing within the brain is concentrated in a
large number of processing engines
The signal processing function within the cortex appears to be concentrated
in an uncountable number of individual signal processing engines. Most of the engines
related to vision can be described as extraction engines that implement various
extraction mechanisms (or signal processing routines). Additional engines, particularly
in the frontal lobe of the brain can be considered cognitive engines implementing other routines.
Engines along the intersection of the frontal lobe and occipital lobe appear to
be primarily involved in the generation of neural signals to control the body.
They can be considered implementation engines.
III. The bandwidth of the signal paths within an engine are very
high
The bandwidth of the majority of the skeletal and sensory nervous system is
apparently limited by the tradeoff between signal bandwidth and signal transmission
velocity with the instantaneous availability of electrical power as a parameter.
The bandwidth of the neural paths within the individual engines of the cortex,
and possibly other portions of the brain are not limited by the above constraint
(although inter-communications paths are).
Because of the extremely short signal paths found within a given engine, the
limiting signal bandwidth of a circuit can be very high. This allows the signal processing
within an engine to proceed at a much higher, and asynchronous, rate than in the
peripheral and interconnecting nervous system. Although not quantified to date, the noise spectrum
associated with the background obtained when recording signals from the cortex
suggest the maximum rate may be on the order of a megahertz or higher.
FINDINGS RELATED TO READING
While many of the chordates,and a few molluscs (squid, etc.) are able to recognize relatively abstract features of objects, such as recognizing objects of different color, and to some extent different shape, even the other primates are not able to perceive the differences between intricately drawn shapes. This unique human capability has allowed the development of communications through writing and printing.
This unique capability has developed in the human through the more advanced evolution of a special analytical channel of vision that lower species have not achieved. This analytical channel is distinctly separate from that studied heretofor. It does not involve the primary visual cortex or the Lateral Geniculate Nuclei of the visual system. These major engines of vision are primarily concerned with the awareness of the environment surrounding the individual.
The unique abilities associated with reading and other procedures involved in the recognition and interpretation of fine spatial detail use a separate visual pathway known as the analytical channel. This channel originates in the very center of the fovea, the foveola, and proceeds to the Precision Optical System (POS) of the midbrain along a distinctly different neural channel than the rest of the information from the retina. The retina and POS combine with the oculomotor subsystem to form a high performance servomechanism (feedback loop) that is critical to the analytical process.
The pretectum of the POS is the key engine of the analytical channel. It both controls the operation of the eye muscles and extracts information from the image projected onto the foveola. It then transmits the information, in vectorial form, directly to area 7 of the cortex via the Pulvinar Pathway. The data does not pass by way of the principal visual cortex in area 17-19.
Area 7 of the cortex plays two roles. Its older role, shared with other animals, is to interpret the awareness information presented to it in vector form from areas 17-22 of the cortex. Its newer role, relative to evolution, is to perform the same functions at a more precise level using the more precise, and timely, information received from the pretectum.
The feature extraction engines of area 7 use the results of their interpretation for two purposes. Critical data, regarding the safety of the animal, is transmitted back to the midbrain, primarily the superior colliculus, in a reflexive mode designed to cause the animal to take evasive or aggressive action. All data is also passed to a saliency map that maintains a perception, using all sensory inputs, of the environment surrounding the animal. This saliency map is the foundation of the memory system.
The information passed to area 7 from both the pretectum and via areas 17-22 is vectorial in nature, involving concepts derived from the context and syntax of the information in the visual field of view.
The pretectum has a major task associated with the extraction of this vectorial information from the image projected onto the foveola. It accomplishes this task by scanning the image using a scan pattern it generates and generally defined as involving the tremor of the eyes. Tremor is a term describing the very fine, virtually continual, vertical and horizontal motion of the eyes. Each component of the tremor is typically less than 40 seconds of arc in amplitude and contains frequency components up to about 150 Hz. These motions are not clinically observable without special instrumentation. They are the key to the operation of the analytical channel and READING.
The reason these precision analytical tasks are performed in the pretectum is to minimize the time delay in signals passing around the servo loops of the POS. If they were performed in the cortex, the additional delay would reduce the reading speed of a typical individual by a factor of three.
(for more detail, go to the reading home page)