<s>
CoDi	B-Algorithm
is	O
a	O
cellular	O
automaton	O
(	O
CA	O
)	O
model	O
for	O
spiking	B-Algorithm
neural	I-Algorithm
networks	I-Algorithm
(	O
SNNs	O
)	O
.	O
</s>
<s>
CoDi	B-Algorithm
is	O
an	O
acronym	O
for	O
Collect	O
and	O
Distribute	O
,	O
referring	O
to	O
the	O
signals	O
and	O
spikes	O
in	O
a	O
neural	B-General_Concept
network	I-General_Concept
.	O
</s>
<s>
CoDi	B-Algorithm
uses	O
a	O
von	O
Neumann	O
neighborhood	O
modified	O
for	O
a	O
three-dimensional	O
space	O
;	O
each	O
cell	O
looks	O
at	O
the	O
states	O
of	O
its	O
six	O
orthogonal	O
neighbors	O
and	O
its	O
own	O
state	O
.	O
</s>
<s>
In	O
a	O
growth	O
phase	O
a	O
neural	B-General_Concept
network	I-General_Concept
is	O
grown	O
in	O
the	O
CA-space	O
based	O
on	O
an	O
underlying	O
chromosome	O
.	O
</s>
<s>
There	O
are	O
four	O
types	O
of	O
cells	O
:	O
neuron	O
body	O
,	O
axon	B-Algorithm
,	O
dendrite	O
and	O
blank	O
.	O
</s>
<s>
Signals	O
are	O
distributed	O
from	O
the	O
neuron	O
bodies	O
via	O
their	O
axon	B-Algorithm
tree	O
and	O
collected	O
from	O
connection	O
dendrites	O
.	O
</s>
<s>
In	O
the	O
CoDi	B-Algorithm
model	O
the	O
neurons	O
sum	O
the	O
incoming	O
signal	O
values	O
and	O
fire	O
after	O
a	O
threshold	O
is	O
reached	O
.	O
</s>
<s>
The	O
output	O
of	O
the	O
neuron	O
bodies	O
is	O
passed	O
on	O
to	O
its	O
surrounding	O
axon	B-Algorithm
cells	O
.	O
</s>
<s>
the	O
direction	O
in	O
which	O
the	O
axon	B-Algorithm
is	O
pointing	O
.	O
</s>
<s>
In	O
an	O
axon	B-Algorithm
cell	O
,	O
the	O
gate	O
points	O
to	O
the	O
neighbor	O
from	O
which	O
the	O
neural	O
signals	O
are	O
received	O
.	O
</s>
<s>
An	O
axon	B-Algorithm
cell	O
accepts	O
input	O
only	O
from	O
this	O
neighbor	O
,	O
but	O
makes	O
its	O
own	O
output	O
available	O
to	O
all	O
its	O
neighbors	O
.	O
</s>
<s>
In	O
this	O
way	O
axon	B-Algorithm
cells	O
distribute	O
information	O
.	O
</s>
<s>
The	O
CoDi	B-Algorithm
model	O
does	O
not	O
use	O
explicit	O
synapses	O
,	O
because	O
dendrite	O
cells	O
that	O
are	O
in	O
contact	O
with	O
an	O
axonal	O
trail	O
(	O
i.e.	O
</s>
<s>
have	O
an	O
axon	B-Algorithm
cell	O
as	O
neighbor	O
)	O
collect	O
the	O
neural	O
signals	O
directly	O
from	O
the	O
axonal	O
trail	O
.	O
</s>
<s>
This	O
results	O
from	O
the	O
behavior	O
of	O
axon	B-Algorithm
cells	O
,	O
which	O
distribute	O
to	O
every	O
neighbor	O
,	O
and	O
from	O
the	O
behavior	O
of	O
the	O
dendrite	O
cells	O
,	O
which	O
collect	O
from	O
any	O
neighbor	O
.	O
</s>
<s>
The	O
strength	O
of	O
a	O
neuron-neuron	O
connection	O
(	O
a	O
synapse	O
)	O
is	O
represented	O
by	O
the	O
number	O
of	O
their	O
neighboring	O
axon	B-Algorithm
and	O
dendrite	O
cells	O
.	O
</s>
<s>
The	O
exact	O
structure	O
of	O
the	O
network	O
and	O
the	O
position	O
of	O
the	O
axon-dendrite	O
neighbor	O
pairs	O
determine	O
the	O
time	O
delay	O
and	O
strength	O
(	O
weight	O
)	O
of	O
a	O
neuron-neuron	O
connection	O
.	O
</s>
<s>
The	O
distributed	O
chromosome	O
technique	O
of	O
the	O
CoDi	B-Algorithm
model	O
makes	O
maximum	O
use	O
of	O
the	O
available	O
CA-space	O
and	O
enables	O
the	O
growth	O
of	O
any	O
type	O
of	O
network	O
connectivity	O
.	O
</s>
<s>
The	O
local	O
connection	O
of	O
the	O
grown	O
circuitry	O
to	O
its	O
chromosome	O
,	O
allows	O
local	O
learning	O
to	O
be	O
combined	O
with	O
the	O
evolution	O
of	O
grown	O
neural	B-General_Concept
networks	I-General_Concept
.	O
</s>
<s>
The	O
blank	O
neighbors	O
,	O
which	O
receive	O
a	O
neural	O
growth	O
signal	O
,	O
turn	O
into	O
either	O
an	O
axon	B-Algorithm
cell	O
or	O
a	O
dendrite	O
cell	O
.	O
</s>
<s>
When	O
designing	O
the	O
CoDi	B-Algorithm
CA-based	O
neural	B-General_Concept
networks	I-General_Concept
model	O
,	O
the	O
objective	O
was	O
to	O
implement	O
them	O
directly	O
in	O
hardware	O
(	O
FPGAs	O
)	O
.	O
</s>
<s>
The	O
CoDi	B-Algorithm
model	O
was	O
implemented	O
in	O
the	O
FPGA	O
based	O
CAM-Brain	O
Machine	O
(	O
CBM	O
)	O
by	O
Korkin	O
.	O
</s>
<s>
CoDi	B-Algorithm
was	O
introduced	O
by	O
Gers	O
et	O
al	O
.	O
</s>
<s>
A	O
specialized	O
parallel	O
machine	O
based	O
on	O
FPGA	O
Hardware	O
(	O
CAM	O
)	O
to	O
run	O
the	O
CoDi	B-Algorithm
model	O
on	O
a	O
large	O
scale	O
was	O
developed	O
by	O
Korkin	O
et	O
al	O
.	O
</s>
<s>
De	O
Garis	O
conducted	O
a	O
series	O
of	O
experiments	O
on	O
the	O
CAM-machine	O
evaluating	O
the	O
CoDi	B-Algorithm
model	O
.	O
</s>
