<s>
NEST	B-Application
is	O
a	O
simulation	B-Application
software	I-Application
for	O
spiking	B-Algorithm
neural	I-Algorithm
network	I-Algorithm
models	O
,	O
including	O
large-scale	O
neuronal	B-General_Concept
networks	I-General_Concept
.	O
</s>
<s>
NEST	B-Application
was	O
initially	O
developed	O
by	O
Markus	O
Diesmann	O
and	O
Marc-Oliver	O
Gewaltig	O
and	O
is	O
now	O
developed	O
and	O
maintained	O
by	O
the	O
NEST	B-Application
Initiative	O
.	O
</s>
<s>
A	O
NEST	B-Application
simulation	O
tries	O
to	O
follow	O
the	O
logic	O
of	O
an	O
electrophysiological	B-Application
experiment	O
that	O
takes	O
place	O
inside	O
a	O
computer	O
with	O
the	O
difference	O
,	O
that	O
the	O
neural	B-General_Concept
system	I-General_Concept
to	O
be	O
investigated	O
must	O
be	O
defined	O
by	O
the	O
experimenter	O
.	O
</s>
<s>
The	O
neural	B-General_Concept
system	I-General_Concept
is	O
defined	O
by	O
a	O
possibly	O
large	O
number	O
of	O
neurons	O
and	O
their	O
connections	B-Application
.	O
</s>
<s>
In	O
a	O
NEST	B-Application
network	O
,	O
different	O
neuron	O
and	O
synapse	B-Application
models	O
can	O
coexist	O
.	O
</s>
<s>
Any	O
two	O
neurons	O
can	O
have	O
multiple	O
connections	B-Application
with	O
different	O
properties	O
.	O
</s>
<s>
Thus	O
,	O
the	O
connectivity	O
can	O
in	O
general	O
not	O
be	O
described	O
by	O
a	O
weight	O
or	O
connectivity	B-Algorithm
matrix	I-Algorithm
but	O
rather	O
as	O
an	O
adjacency	B-Data_Structure
list	I-Data_Structure
.	O
</s>
<s>
These	O
devices	O
write	O
their	O
data	O
either	O
to	O
memory	B-General_Concept
or	O
to	O
file	O
.	O
</s>
<s>
NEST	B-Application
is	O
extensible	O
and	O
new	O
models	O
for	O
neurons	O
,	O
synapses	B-Application
,	O
and	O
devices	O
can	O
be	O
added	O
.	O
</s>
<s>
The	O
figure	O
shows	O
the	O
spiking	B-Algorithm
activity	I-Algorithm
of	O
50	O
neurons	O
as	O
a	O
raster	O
plot	O
.	O
</s>
<s>
Each	O
dot	O
corresponds	O
to	O
a	O
spike	B-Algorithm
of	O
the	O
respective	O
neuron	O
at	O
a	O
given	O
time	O
.	O
</s>
<s>
The	O
lower	O
part	O
of	O
the	O
figure	O
shows	O
a	O
histogram	B-Algorithm
with	O
the	O
mean	O
firing-rate	O
of	O
the	O
neurons	O
.	O
</s>
<s>
Static	O
synapses	B-Application
with	O
homogeneous	O
or	O
heterogeneous	O
weight	O
and	O
delay	O
.	O
</s>
<s>
Neuromodulated	O
synapses	B-Application
,	O
using	O
Dopamine	O
.	O
</s>
<s>
By	O
default	O
,	O
spikes	B-Algorithm
fall	O
onto	O
the	O
grid	O
,	O
defined	O
by	O
the	O
simulation	O
time-step	O
.	O
</s>
<s>
Some	O
models	O
support	O
spike-exchange	O
in	O
continuous	O
time	O
.	O
</s>
<s>
Support	O
for	O
multi-threaded	O
simulation	O
,	O
using	O
OpenMP	B-Application
or	O
POSIX	B-Operating_System
Threads	I-Operating_System
.	O
</s>
<s>
Parallelization	O
is	O
handled	O
semi-automatically	O
by	O
NEST	B-Application
's	O
simulation	O
kernel	O
.	O
</s>
<s>
Supra-linear	O
to	O
linear	O
scaling	O
for	O
up	O
to	O
10000	O
cores	B-Architecture
.	O
</s>
<s>
NEST	B-Application
development	O
was	O
started	O
in	O
1993	O
by	O
Markus	O
Diesmann	O
and	O
Marc-Oliver	O
Gewaltig	O
at	O
the	O
Ruhr	O
University	O
Bochum	O
,	O
Bochum	O
,	O
Germany	O
and	O
the	O
Weizmann	O
Institute	O
of	O
Science	O
in	O
Rehovot	O
,	O
Israel	O
.	O
</s>
<s>
In	O
2001	O
,	O
the	O
software	O
changed	O
its	O
name	O
from	O
SYNOD	O
to	O
NEST	B-Application
.	O
</s>
<s>
Until	O
2004	O
,	O
NEST	B-Application
was	O
exclusively	O
developed	O
and	O
used	O
by	O
the	O
founding	O
members	O
of	O
the	O
NEST	B-Application
Initiative	O
.	O
</s>
<s>
Since	O
then	O
,	O
NEST	B-Application
was	O
released	O
regularly	O
,	O
about	O
once	O
or	O
twice	O
per	O
year	O
.	O
</s>
<s>
Since	O
2007	O
,	O
NEST	B-Application
supports	O
hybrid	O
parallelism	O
,	O
using	O
POSIX	B-Operating_System
threads	I-Operating_System
and	O
MPI	B-Application
.	O
</s>
<s>
In	O
2008	O
,	O
the	O
stack-based	B-Language
simulation	O
language	O
SLI	O
was	O
superseded	O
by	O
a	O
modern	O
Python	B-Language
interface	O
,	O
however	O
,	O
the	O
old	O
simulation	O
language	O
is	O
still	O
used	O
internally	O
.	O
</s>
<s>
At	O
the	O
same	O
time	O
,	O
the	O
simulator	O
independent	O
specification	O
language	O
PyNN	O
was	O
developed	O
with	O
support	O
for	O
NEST	B-Application
.	O
</s>
<s>
In	O
2012	O
,	O
the	O
NEST	B-Application
Initiative	O
changed	O
the	O
license	O
from	O
the	O
proprietary	O
NEST	B-Application
License	O
to	O
GNU	B-License
GPL	I-License
V2	O
or	O
later	O
.	O
</s>
<s>
NEST	B-Application
primary	O
user	O
interface	O
is	O
PyNEST	O
,	O
a	O
Python	B-Language
package	O
that	O
controls	O
the	O
NEST	B-Application
simulation	O
kernel	O
.	O
</s>
<s>
PyNEST	O
aims	O
at	O
easy	O
usability	O
and	O
seamless	O
interaction	O
with	O
Python	B-Language
and	O
its	O
libraries	O
.	O
</s>
<s>
PyNN	O
is	O
a	O
simulator	O
independent	O
language	O
for	O
neural	O
simulations	O
,	O
which	O
supports	O
NEST	B-Application
as	O
well	O
as	O
BRIAN	B-Application
,	O
NEURON	O
,	O
as	O
well	O
as	O
neuromorphic	O
hardware	O
.	O
</s>
<s>
NEST	B-Application
also	O
maintains	O
its	O
own	O
simulation	O
language	O
interpreter	B-Application
(	O
SLI	O
)	O
,	O
which	O
understands	O
a	O
simple	O
Stack-oriented	B-Language
programming	I-Language
language	I-Language
that	O
is	O
influenced	O
by	O
PostScript	B-Language
.	O
</s>
