Diagram information
This page gives information on the diagrams that appear on various pages on this website mainly relating to
afferent processing, particularly on the
afferent processing examples page, but and also
symbol schema relationships.
- All examples shown in diagrams on this set of web pages
are simplified and idealistic versions of reality (see example right).
- Individual “neurons” are shown as square boxes, of different sizes,
usually with arrows in and out.
- Some have letters inside the boxes so that they can be identified in the text.
- Note that these do not represent real neurons, but simplistic model ones - see below for details.
- An arrowed line between neurons represents the passing of an electrical signal from the axon of one
neuron via a synapse connection to the dendrite or cell body
of another neuron, in the direction shown by the arrow.
- For clarity and simplicity, not all connections are shown in all cases.
- Black arrowed straight lines represent incoming data and
afferent processing connections.
- These indicate the passing of signals in the direction
from where data comes in towards symbol schemas.
- Red arrowed lines (usually curved) represent efferent connections
in the opposite direction.
- These indicate the passing of signals from symbol schemas back towards where the data came in.
- Green arrowed lines (usually curved) are also efferent connections
but especially long-range ones from the self symbol schema back towards where the data originated.
- These links would be responsible for a number of things including attention and
providing feeling or meaning relating to the symbol schema in question.
- Black arrowed straight dashed lines indicate data signals or connections that were active in the past
but are not active at the time shown in the diagram.
- These are included to show where previous data came from.
- Symbol schemas are drawn as ovals with dotted-line borders.
- The dotted-lines indicate that they are degenerate sets of neurons and synapse connections with fuzzy boundaries.
- The name of the concept that the symbol schema represents is written in capital letters in the oval.
- The name of a symbol schema is sometimes put in curly brackets or braces, for example {Frisbee}, as
shorthand in textual descriptions (see symbol schemas - notation).
- Connections between symbol schemas are drawn with straight non-arrowed black lines
which represent multiple connections in both directions.
- There are a number of differences between the diagrams and reality:
- A single neuron in the diagrams represents a much simplified
model of a neuron that I call an ABCD neuron, or Absolutely Basic Coincidence Detecting neuron.
- An ABCD neuron has only two inputs so can detect only one coincidence of two signals arriving at the same time
(or very nearly the same time).
- A real neuron can have many hundreds or even thousands of inputs so can potentially detect
many millions of different coincidences of two or more signals arriving within a short period of time.
- The signalling of a real neuron can also be affected by neuromodulation,
which involves the production of various signalling chemicals by more remote neurons, glial cells,
or various places outside the brain (which are then usually called hormones).
- The brain has a large amount of resilience or degeneracy in the form of duplication, so many neurons may
detect the same coincidence. This duplication is not shown in the diagrams
(see the explanation of degeneracy relating to symbol schemas).
- So the functionality of an ABCD neuron is a tiny fraction of the functionality of one neuron, which may
be the same as in many other real neurons.
- The combination of many ABCD neurons together can approximate the total functionality of those neurons;
this is explained further in the page on ABCD neurons.
- There is a many-to-many relationship of real neurons to ABCD neurons, but there are always going
to be far more ABCD neurons than real neurons required to perform the same functionality (to detect the same number of coincidences).
- What is shown as a single synapse connection between two ABCD neurons in the diagrams
is likely to represent many real synapse connections and sometimes also more remote pseudo-connections created by neuromodulation.
- The first reason for this is because of the duplication and resilience in the brain mentioned above.
- The second reason is because of the influence of neuromodulation on a neuron, also mentioned above.
- What is shown as a direct connection between two ABCD neurons may not be direct in reality between real neurons,
other intermediate neurons may be involved, but the effect will be the same.
- In some places, the brain has neurons which simply act as relay stations to pass on signals.
- There may be cases, however, where the exact timing is important, so the short delay in
passing on a signal can be of relevance.
- What is shown (or implied) as a single signal that is sent between two ABCD neurons may actually
be many signals sent between many real neurons, but the effect will be the same.
- The implication that a neuron only sends a signal when it is activated also is a simplification;
in reality, many neurons are firing a lot of the time, but change their firing rate when certain signals are received,
but there will still be a coincidence involved in these signals
(see neuron - signals).
Page last uploaded
Sun Feb 11 11:41:07 2024 MST
