CHECK OUT MY RECENTLY PUBLISHED PAPERS:
Exploring The Possibility Of An Elimination Algorithm as the Basis for Human Intuition: A Study of a Successful Expert System for Eye Disease Diagnosis
Unlocking The Science Of Emotions Through Pattern Recognition: Establishing Emotions As A Proper Field Of Study
The olfactory sense has processed odor data using a specific coding principle for hundreds of millions of years. That neural array principle for internal representation enabled instant recognition of odors by the earliest "nose brains" in lower vertebrates. An evaluation of smells enabled those primitive life forms to distinguish whether objects were threatening, consumable, or irrelevant.
As life evolved, nature added more and more sensory evaluation systems and motor organs to improve the quality of decision delivery processes, culminating finally in the advanced human systems. But, even as they evolved over untold generations, the myriad intelligent subsystems of animals used the same coding principle for internal representation.
The
Olfactory Sense
How Does The Mind Recognize Events?
The
olfactory system identifies objects and events linked to chemical
molecules in the air. The data cascades through sequences of
geographically arranged arrays of neural junctions in the system. In
the process, the olfactory system identifies both subtle and complex
relationships in the patterns detected during varying neural firing
cycles. The power of this system, which processes the olfactory sense
alone, can be seen in the remarkable intuitive capabilities of
dogs.
The
area of the olfactory epithelium in dogs is about forty times larger
than in humans. The animals can detect human scent on a glass slide
that has been lightly fingerprinted and left outdoors for as much as
two weeks, or indoors for as long as a month. With their hunting
instincts, they can also sniff the footprints of a person and
identify the direction of a trail. The animal's olfactory sense
connects the relative odor strength difference between footprints
barely a few feet apart to sense the direction in which the person was
walking. Pattern recognition of sensory data can yield such complex
meanings.
The
Olfactory Sense
What Is The 1st Step In The Olfactory Process?
The
olfactory process begins with an analysis of molecules of volatile
chemical compounds in the air. Approximately 50 million primary
sensory receptor cells in the epithelium in the roof of the two nasal
cavities of the human nose evaluate the molecules. Those substances
must possess certain molecular properties to enable the olfactory
process. The molecules generally need to have a level of water
solubility, a sufficiently high vapor pressure, low polarity, some
ability to dissolve in fat, surface activity and a molecular weight
below 294. The olfactory sense can distinguish among a practically
infinite number of such chemical compounds at very low
concentrations.
The
Olfactory Sense
What Is The Internal Language Of The Nervous System?
Neurons
encode information from sensory data into a common internal language.
When particular molecules bind to receptor cells, structural changes
occur within the cell. These changes generate action potentials
reversing polarity across the membranes of the axons of the nerve
cells. The process triggers an all or nothing output impulse, lasting
about 5 milliseconds. Across billions of nerve cells, similar nerve
impulses enable myriad independent intelligences to speak to each
other, using a coded internal language.
A
computer converts physical keystrokes into binary data, which is
processed using a variety of programming languages. Problem specific
languages are needed to manage each task. There is no single language
in which problems can be represented in computers to enable them to
simultaneously handle chess, chemical analysis and banking. But, the
mind fathoms the whole world through a common internal language. The
olfactory sense was one of the earliest to use the unique neural
code, which is central to this language. That neural code enables the
senses, emotions and motor controls to interact. That code internally
represents varied types of data in a single format.
The
Olfactory Sense
What Is The Role Of Arrays In Pattern Recognition?
The
code enables a conversion of molecular data into event identification
data. Each type of data is represented as a combinatorial neural
firing code in a geographically arranged array of cell addresses.
Each address in such an array represents one element of a pattern of
that particular data type. The olfactory system converts elements in
the odor data array into combinatorial elements of an array
representing events. The process cascades the data through a sequence
of three arrays in progressive pattern recognition steps. There is a
receptor array, a glomeruli array and a mitral cell array.
The
process begins with the receptor array, which identifies molecules in
the air and ends in a mitral cell array, which identifies objects and
events. The first array in the olfactory epithelium recognizes
specific molecules. The array has a random arrangement of 50 million
receptors, each recognizing specific groups of molecules. Recognition
impulses from receptors travel to a second array of glomeruli on the
olfactory bulb. Each mitral cell is activated only by one glomerulus,
but is extensively linked through interneurons to other mitral
cells.
The
glomeruli array and the mitral cell array carry combinatorial
memories. The glomeruli array recognizes the activated receptors
among the 50 million elements to fire patterns in its 1000 element
array. That combinatorial message narrows down the molecular
disposition of the odor. The mitral cell array interprets that
message to output its own combinatorial message. The mitral cell
message indicates to the nervous system that the breathed in
molecules in the nose originate from a specific event. The memories
of other arrays in the nervous system recognize that event to
originate from the smell of an orange, or from the odor of spoilt
meat. The mitral cell array fires the final object/event recognition
combinatorial message to other intelligences in the system.
The
Olfactory Sense
What Is The Data Handling Capacity Of Combinatorial Codes?
The
nervous system projects data from one region to another through
combinatorial arrays. During their initial growth, the output axons
of nerve cells grow from one region to another and “map” on to
specific target regions. The cells always connect from array to array
in geographically correct locations, where neighborhood relationships
are strictly maintained. An olfactory neuron carries a message about
odors. A nearby neuron in another array may carry a completely
unrelated message.
As
in parallel ports in computers, combinatorial codes, with such
“on/off” elements, can store a galactic mass of information. An
array with just one hundred “on/off” elements can fire over 1,
000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000,
000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000,
000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000,
000, 000, 000, 000, 000, 000, 000, 000, 000, 000 unique possible
combinations! The human olfactory glomeruli array contains 1000
elements!
Some
glomeruli fire (On) on recognition of specific receptor firing
combinations indicating recognition of particular molecules. Those
glomeruli, which do not recognize those molecules remain inhibited
(Off). On interpreting this incoming pattern from glomeruli, the
mitral cell array fires. In this system, the final combinatorial
message identifies an object or event.
The
Olfactory Sense
When Was Combinatorial Coding Discovered?
Researchers
announced (Nobel Prize 2004) the use of combinatorial coding by the
olfactory system in 1999. According to them, a single receptor in the
olfactory epithelium can recognise several different odour molecules.
When any one of these molecules hits the receptor, the nerve cell
sends a signal to a specific glomerulus. They found that the same
odour can be recognised by several different receptors and a
glomerulus with a given receptor type responds to several different
odours. Combinatorial coding carries the message.
As
an example, the chemical octanol was found to be recognised by a
combination of four different glomeruli. As against this, octanic
acid, in which the hydroxyl group of octanol is replaced by a
carboxyl group, was recognised by the same four glomeruli, plus an
additional four. Small molecular differences completely change the
smell of a chemical. While octanol has an orangy rose-like scent,
octanic acid smells like sweaty feet. Leslie Vosshall reports that,
in her lab, ordinary volunteers, (not wine tasters or perfumers),
could clearly distinguish between different combinations of 128 odor
molecules, indicating an average human ability to differentiate
between 1 trillion smells.
The
Olfactory Sense
What Is The Exponential Growth Search Problem?
Identification
of a specific pattern in an astronomically large assembly of patterns
presents a huge search problem. Combinatorial arrays can present
trillions of overlapping patterns, where each pattern may have a
significantly different meaning. Both octanol and octanic acid were
recognized by four glomeruli, (say, A, B, C and D). Octanic acid
alone was recognized by an additional four glomeruli, (say, E, F, G
and H). So, if octanic acid was recognized, ABCDEFGH would fire. In
the process, both octanol and octanic acid would be identified.
Accurate recognition of overlapping patterns in such a large database
appears a seemingly insurmountable problem.
The
Olfactory Sense
Is There An Algorithm, Which Solves The Search Problem?
There
is no known search algorithm, which can identify a single pattern
from a search space containing trillions of overlapping patterns.
But, this website suggests that intuition
is a powerful algorithm,
which can instantly search large databases. The process eliminates
unrecognized possibilities, using coded inhibition by nerve cells. In
the octanol/octanic acid case, the firing by glomerulus G, or H would
indicate that the odor does not come from octanol. The mitral cell
array, which can represent millions of odors, would inhibit the
“octanol” possibility.
Throughout
the nervous system, this process of intelligently coded inhibition,
explains the secret of instant recognition. The brain is known to use
inhibition for highlighting the importance of messages. If the touch
of a single hair is critical information, all surrounding sensory
inputs are shut off to highlight the message. Similar automatic
emphasizing of contrasts takes place for both visual, auditory and
sensory inputs. The precisely maintained neighborhood relationships
of the projected arrays and mapped neural pathways enable such
inhibition throughout the system.
The
brain actively participates in closing off irrelevant sensory inputs.
Throughout the nervous system, the firing of a single cell is known
to "shut down" millions of cells. There are neural circuits
which switch off other circuits when their own areas are energized.
There is evidence that the mind carries such systematic elimination
beyond logic. This is illustrated in the popular vision experiment,
where a drawing can be interpreted as a vase, or two faces facing
each other. The mind eliminates one interpretation to recognize the
other - a vase, or two faces. Evidently each recognition path acts
powerfully to inhibit the other.
The
Olfactory Sense
Does The Nervous System Use Inhibition?
Inhibition
comes from many inputs to enable the mitral cell array to fire
indicating the recognition of the smell of an orange. Lateral
inhibition between mitral cells is kniown to occur through
interneurons known as granule cells. The glomeruli are also permeated
by dendrites from the mitral cells triggering inhibition. The output
axons of the mitral cells travel through the olfactory nerve tract to
many regions of the brain, including the olfactory cortex and the
amygdala. These regions further interpret the data and send feedback
messages. These messages can also trigger inhibition.
Each
mitral cell receives thousands of dendritic inputs, each representing
a specific data type. A massive combinatorial memory enables each
mitral cell to fire, or to become inhibited. Researchers report a
significant process of inhibition in the mitral cell array. The
process inhibits unrecognized elements. The array finally reports the
recognition of the smell of an orange.
The
Olfactory Sense
Is There A Hierarchy Of Arrays In The Nervous System?
Incoming
data in the nervous system passes through hierarchies of processing
arrays. At the highest level, the prefrontal array evaluates the
final data. The arrays in the amygdala, the limbic system and the
hypothalamus are lower level control centers, which substantially
manage the system. Experimental studies of the impact of destruction
of localized regions in animals point to a hierarchy of such control
systems. As higher levels are included with the spinal cord below the
cut off section, more effective controls are retained. With
transection below the hypothalamus, minor reflex adjustments of
systems survive, but are not integrated.
With
transection above the hypothalamus, separating it from the limbic
system, effective controls are maintained within a moderate range of
conditions. Innate drives and motivated behavior are preserved,
including feeding, drinking, apparent satiation, and copulatory
responses. But animals may attack, try to eat, drink or copulate with
inappropriate objects. But if the connections between the limbic
system and the hypothalamus survive and only the frontal cortex is
cut off, normal homeostasis is preserved even in a wide range of
adverse conditions. The array in the limbic system can emotionally
manage our lives. Human level intelligence operates, often
helplessly, from the prefrontal array.
The
Olfactory Sense
Does Evolution Have An Entrenched Quality?
Francois
Jacob noted an entrenched quality of evolution. “In contrast to the
engineer, evolution does not produce innovations from scratch. It
works on what already exists, either transforming a system to give it
a new function or combining several systems to produce a more complex
one.” Nature began with combinatorial coding in the olfactory sense
of early “nose brains.” That coding could store massive inherited
and acquired knowledge in the many self contained regions within the
network.
Each
is an independent intelligence, which communicates with the rest of
the network through this common internal representation of a
particular type of data. Each one of millions of smells, emotional
expressions, or motor control impulses are each represented and
recognized as a pattern of firing by specific neural arrays. Each
element in the array recognizes combinations and contributes to the
network. Nature worked on that process over millions of years, adding
functions and features, which finally culminated in the awesome
wonder of human intelligence.