<s>
Spike-and-wave	B-Algorithm
is	O
a	O
pattern	O
of	O
the	O
electroencephalogram	B-Application
(	O
EEG	B-Application
)	O
typically	O
observed	O
during	O
epileptic	O
seizures	O
.	O
</s>
<s>
A	O
spike-and-wave	B-Algorithm
discharge	O
is	O
a	O
regular	O
,	O
symmetrical	O
,	O
generalized	O
EEG	B-Application
pattern	O
seen	O
particularly	O
during	O
absence	O
epilepsy	O
,	O
also	O
known	O
as	O
‘	O
petit	O
mal’	O
epilepsy	O
.	O
</s>
<s>
The	O
first	O
spike-and-wave	B-Algorithm
pattern	O
was	O
recorded	O
in	O
the	O
early	O
twentieth	O
century	O
by	O
Hans	O
Berger	O
.	O
</s>
<s>
The	O
spike-and-wave	B-Algorithm
pattern	O
is	O
most	O
commonly	O
researched	O
in	O
absence	O
epilepsy	O
,	O
but	O
is	O
common	O
in	O
several	O
epilepsies	O
such	O
as	O
Lennox-Gastaut	O
syndrome	O
(	O
LGS	O
)	O
and	O
Ohtahara	O
syndrome	O
.	O
</s>
<s>
Today	O
,	O
most	O
of	O
the	O
research	O
is	O
focused	O
on	O
the	O
origin	O
of	O
the	O
generalized	O
bilateral	O
spike-and-wave	B-Algorithm
discharge	O
.	O
</s>
<s>
One	O
proposal	O
suggests	O
that	O
a	O
thalamocortical	O
(	O
TC	O
)	O
loop	O
is	O
involved	O
in	O
the	O
initiation	O
spike-and-wave	B-Algorithm
oscillations	O
.	O
</s>
<s>
Although	O
there	O
are	O
several	O
theories	O
,	O
the	O
use	O
of	O
animal	O
models	O
has	O
provided	O
new	O
insight	O
on	O
spike-and-wave	B-Algorithm
discharge	O
in	O
humans	O
.	O
</s>
<s>
History	O
of	O
generalized	O
epilepsy	O
with	O
absence	O
seizures	O
are	O
dated	O
to	O
the	O
eighteenth	O
century	O
,	O
however	O
the	O
inventor	O
of	O
the	O
electroencephalogram	B-Application
(	O
EEG	B-Application
)	O
,	O
Hans	O
Berger	O
,	O
recorded	O
the	O
first	O
EEG	B-Application
of	O
an	O
absence	O
seizure	O
in	O
the	O
1920s	O
,	O
which	O
led	O
the	O
way	O
for	O
the	O
general	O
notion	O
of	O
spike-and-wave	B-Algorithm
electrophysiology	O
.	O
</s>
<s>
His	O
first	O
recording	O
of	O
a	O
human	O
EEG	B-Application
was	O
made	O
in	O
1924	O
using	O
a	O
galvanometer	O
,	O
but	O
his	O
results	O
were	O
very	O
crude	O
and	O
showed	O
small	O
,	O
undefined	O
oscillations	O
.	O
</s>
<s>
He	O
continued	O
to	O
refine	O
his	O
technique	O
and	O
increase	O
the	O
sensitivity	O
to	O
the	O
galvanometer	O
,	O
in	O
which	O
he	O
accumulated	O
many	O
EEGs	B-Application
of	O
individuals	O
with	O
and	O
without	O
a	O
brain	O
malfunction	O
or	O
disorder	O
.	O
</s>
<s>
Hans	O
Berger	O
published	O
his	O
findings	O
in	O
1933	O
,	O
however	O
his	O
results	O
did	O
not	O
give	O
a	O
definitive	O
characterization	O
of	O
the	O
general	O
EEG	B-Application
pattern	O
seen	O
during	O
an	O
epileptic	O
seizure	O
.	O
</s>
<s>
Lennox	O
provided	O
a	O
clear	O
description	O
of	O
EEG	B-Application
spike-and-wave	B-Algorithm
patterns	O
during	O
a	O
petit	O
mal	O
epileptic	O
seizure	O
.	O
</s>
<s>
An	O
intracellular	O
recording	O
performed	O
by	O
DA	O
Pollen	O
in	O
1964	O
revealed	O
that	O
the	O
"	O
spike	B-Algorithm
"	O
aspect	O
of	O
the	O
phenomenon	O
was	O
associated	O
with	O
neuronal	B-Algorithm
firing	I-Algorithm
and	O
the	O
"	O
wave	O
"	O
aspect	O
was	O
associated	O
with	O
hyperpolarization	O
.	O
</s>
<s>
The	O
spike-and-wave	B-Algorithm
pattern	O
seen	O
during	O
an	O
absence	O
seizure	O
is	O
the	O
result	O
of	O
a	O
bilateral	O
synchronous	O
firing	O
of	O
neurons	O
ranging	O
from	O
the	O
neocortex	O
(	O
part	O
of	O
the	O
cerebral	O
cortex	O
)	O
to	O
the	O
thalamus	O
,	O
along	O
the	O
thalamocortical	O
network	O
.	O
</s>
<s>
The	O
EEG	B-Application
“	O
spike	B-Algorithm
”	O
of	O
the	O
spike-and-wave	B-Algorithm
complex	O
corresponds	O
to	O
the	O
depolarization	O
of	O
the	O
neuronal	O
membrane	O
potential	O
,	O
also	O
called	O
a	O
paroxysmal	O
depolarizing	O
shift	O
(	O
PDS	O
)	O
.	O
</s>
<s>
The	O
initial	O
understanding	O
behind	O
the	O
mechanism	O
of	O
the	O
PDS	O
was	O
that	O
it	O
was	O
caused	O
by	O
a	O
very	O
large	O
EPSP	O
(	O
excitatory	O
postsynaptic	O
potential	O
)	O
in	O
the	O
absence	O
of	O
synaptic	O
inhibition	O
,	O
which	O
relayed	O
the	O
action	B-Algorithm
potentials	I-Algorithm
in	O
the	O
neurons	O
by	O
triggering	O
activation	O
of	O
voltage-gated	O
channels	O
.	O
</s>
<s>
The	O
voltage-gated	O
sodium	O
channels	O
cause	O
transitory	O
sodium	O
current	O
into	O
the	O
cell	O
,	O
which	O
generates	O
the	O
action	B-Algorithm
potential	I-Algorithm
.	O
</s>
<s>
In	O
an	O
epileptic	O
seizure	O
,	O
there	O
are	O
periods	O
of	O
a	O
sustained	O
depolarization	O
,	O
which	O
cause	O
a	O
train	O
of	O
action	B-Algorithm
potentials	I-Algorithm
followed	O
by	O
a	O
repolarization	O
and	O
hyperpolarization	O
phase	O
.	O
</s>
<s>
The	O
train	O
of	O
action	B-Algorithm
potentials	I-Algorithm
constitutes	O
the	O
“	O
spike	B-Algorithm
”	O
phase	O
,	O
and	O
the	O
repolarization	O
and	O
hyperpolarization	O
constitute	O
the	O
“	O
wave	O
”	O
phase	O
.	O
</s>
<s>
Therefore	O
,	O
the	O
theory	O
that	O
spike-and-wave	B-Algorithm
activity	O
is	O
caused	O
by	O
a	O
giant	O
EPSP	O
due	O
to	O
the	O
decrease	O
or	O
the	O
absence	O
of	O
IPSPs	O
(	O
inhibitory	O
postsynaptic	O
potentials	O
)	O
is	O
not	O
accepted	O
as	O
a	O
general	O
mechanism	O
for	O
epileptic	O
activity	O
.	O
</s>
<s>
This	O
change	O
in	O
ion	O
concentration	O
gradient	O
causes	O
the	O
GABAA	O
inhibitory	O
current	O
to	O
surpass	O
the	O
reversal	B-Algorithm
potential	I-Algorithm
,	O
leading	O
to	O
an	O
efflux	O
of	O
the	O
chloride	O
ions	O
.	O
</s>
<s>
Metabotropic	O
glutamate	O
receptors	O
(	O
mGluRs	O
)	O
in	O
the	O
thalamocortical	O
network	O
have	O
also	O
shown	O
to	O
display	O
some	O
role	O
in	O
the	O
generation	O
of	O
spike-and-wave	B-Algorithm
discharges	O
(	O
SWDs	O
)	O
associated	O
with	O
absence	O
epilepsy	O
.	O
</s>
<s>
These	O
studies	O
show	O
that	O
an	O
increase	O
in	O
the	O
expression	O
and/or	O
activity	O
of	O
mGlu4	O
receptors	O
is	O
associated	O
with	O
spike-and-wave	B-Algorithm
discharges	O
seen	O
in	O
absence	O
seizures	O
.	O
</s>
<s>
The	O
use	O
of	O
animal	O
models	O
,	O
such	O
as	O
cats	O
,	O
for	O
studying	O
spike-and-wave	B-Algorithm
discharges	O
,	O
has	O
provided	O
useful	O
data	O
for	O
studying	O
epilepsy	O
in	O
humans	O
.	O
</s>
<s>
The	O
spike-and-wave	B-Algorithm
discharges	O
seen	O
in	O
feline	O
generalized	O
penicillin	O
epilepsy	O
(	O
FGPE	O
)	O
are	O
very	O
similar	O
to	O
the	O
spike-and-wave	B-Algorithm
discharges	O
of	O
a	O
human	O
absence	O
seizure	O
.	O
</s>
<s>
The	O
use	O
of	O
rats	O
has	O
also	O
been	O
a	O
common	O
method	O
for	O
studying	O
the	O
spike-and-wave	B-Algorithm
phenomenon	O
.	O
</s>
<s>
The	O
rats	O
from	O
these	O
two	O
strains	O
show	O
spontaneously	O
occurring	O
absence	O
seizures	O
that	O
consist	O
of	O
typical	O
spike-and-wave	B-Algorithm
activity	O
seen	O
on	O
an	O
EEG	B-Application
.	O
</s>
<s>
In	O
both	O
models	O
,	O
electrophysiological	O
data	O
showed	O
that	O
spike-and-waves	B-Algorithm
are	O
initiated	O
in	O
the	O
somatosensory	O
cortex	O
and	O
then	O
spread	O
rapidly	O
to	O
the	O
motor	O
cortex	O
and	O
thalamic	O
nuclei	O
.	O
</s>
<s>
Using	O
in	O
vivo	O
intracellular	O
recordings	O
,	O
it	O
was	O
found	O
in	O
the	O
GAERS	O
that	O
spike-and-wave	B-Algorithm
are	O
initiated	O
in	O
layer	O
5/6	O
neurons	O
of	O
the	O
somatosensory	O
cortex	O
.	O
</s>
<s>
Another	O
possible	O
initiation	O
pattern	O
tested	O
in	O
rats	O
suggested	O
the	O
thalamocortical	O
(	O
TC	O
)	O
loop	O
is	O
involved	O
in	O
the	O
initiation	O
of	O
spike-and-wave	B-Algorithm
oscillations	O
under	O
certain	O
conditions	O
.	O
</s>
<s>
However	O
,	O
spontaneous	O
spike-and-wave	B-Algorithm
discharges	O
were	O
observed	O
in	O
epileptic	O
rats	O
when	O
the	O
medium	O
oscillations	O
became	O
synchronized	O
,	O
suggesting	O
a	O
dependence	O
of	O
the	O
two	O
.	O
</s>
<s>
However	O
,	O
since	O
medium	O
ranged	O
oscillations	O
only	O
developed	O
into	O
spike-and-wave	B-Algorithm
discharges	O
spontaneously	O
,	O
genetic	O
factors	O
also	O
seem	O
to	O
contribute	O
to	O
the	O
initiation	O
of	O
synchronized	O
oscillations	O
.	O
</s>
<s>
These	O
genetic	O
factors	O
may	O
contribute	O
to	O
spike-and-wave	B-Algorithm
oscillations	O
by	O
decreasing	O
the	O
action	B-Algorithm
potential	I-Algorithm
threshold	O
in	O
reticular	O
cells	O
,	O
making	O
them	O
more	O
excitable	O
and	O
potentially	O
easier	O
to	O
initiate	O
synchronized	O
firing	O
.	O
</s>
<s>
Another	O
study	O
has	O
shown	O
that	O
these	O
medium	O
oscillations	O
have	O
led	O
to	O
spike-and-wave	B-Algorithm
discharges	O
.	O
</s>
<s>
The	O
activity	O
of	O
the	O
primary	O
and	O
secondary	O
cortical	O
regions	O
,	O
as	O
well	O
as	O
the	O
adjacent	O
insular	O
cortex	O
were	O
recorded	O
using	O
an	O
EEG	B-Application
and	O
where	O
applied	O
with	O
electrical	O
stimulation	O
.	O
</s>
<s>
The	O
findings	O
here	O
showed	O
that	O
the	O
onset	O
of	O
spike-and-wave	B-Algorithm
discharged	O
were	O
followed	O
by	O
5	O
–	O
9Hz	O
oscillations	O
in	O
these	O
cortical	O
regions	O
as	O
well	O
.	O
</s>
<s>
Research	O
on	O
ELP4	O
has	O
been	O
linked	O
the	O
gene	O
to	O
a	O
centrotemporal	O
sharp	O
spike	B-Algorithm
phenotype	O
.	O
</s>
<s>
This	O
mutation	O
may	O
be	O
responsible	O
for	O
a	O
predisposition	O
to	O
spike-and-wave	B-Algorithm
discharges	O
,	O
as	O
well	O
as	O
other	O
neurodevelopmental	O
disorders	O
.	O
</s>
<s>
Another	O
study	O
revealed	O
that	O
glucose	O
may	O
also	O
be	O
relevant	O
to	O
spike-and-wave	B-Algorithm
occurrence	O
in	O
mice	O
that	O
contained	O
a	O
knock-in	O
of	O
the	O
human	O
GABA(A )	O
γ2(R43Q )	O
mutation	O
,	O
which	O
has	O
been	O
known	O
to	O
be	O
a	O
genetic	O
factor	O
involved	O
in	O
the	O
causation	O
of	O
absence	O
epilepsy	O
.	O
</s>
<s>
This	O
reduction	O
in	O
blood	O
glucose	O
led	O
to	O
double	O
the	O
occurrence	O
of	O
spike-and-wave	B-Algorithm
activity	O
.	O
</s>
<s>
Bursts	O
of	O
generalized	O
spike-and-wave	B-Algorithm
discharges	O
lasting	O
two	O
seconds	O
or	O
longer	O
is	O
considered	O
an	O
absence	O
seizure	O
.	O
</s>
<s>
Typical	O
and	O
atypical	O
absence	O
seizures	O
display	O
two	O
different	O
kinds	O
of	O
spike-and-wave	B-Algorithm
patterns	O
.	O
</s>
<s>
Typical	O
absence	O
seizures	O
are	O
described	O
by	O
generalized	O
spike-and-wave	B-Algorithm
patterns	O
on	O
an	O
EEG	B-Application
with	O
a	O
discharge	O
of	O
2.5Hz	O
or	O
greater	O
.	O
</s>
<s>
The	O
spike-and-wave	B-Algorithm
pattern	O
seen	O
here	O
is	O
more	O
irregular	O
than	O
the	O
generalized	O
pattern	O
and	O
also	O
seems	O
to	O
be	O
slower	O
.	O
</s>
<s>
Lennox-Gastaut	O
syndrome	O
(	O
LGS	O
)	O
is	O
a	O
childhood	O
epileptic	O
encephalopathy	O
characterized	O
with	O
generalized	O
seizures	O
and	O
slow	O
spike-wave	O
activity	O
while	O
awake	O
.	O
</s>
<s>
LGS	O
is	O
a	O
combination	O
of	O
atonic	O
absences	O
,	O
tonic	O
seizures	O
,	O
cognitive	O
deterioration	O
,	O
and	O
slow	O
spike-wave	O
activity	O
in	O
the	O
EEG	B-Application
.	O
</s>
<s>
Cognitive	O
deterioration	O
with	O
high-frequency	O
spike-wave	O
activity	O
affects	O
most	O
patients	O
2	O
–	O
9	O
years	O
old	O
with	O
generalized	O
seizures	O
.	O
</s>
<s>
This	O
syndrome	O
is	O
characterized	O
on	O
an	O
EEG	B-Application
by	O
high	O
voltage	O
bursts	O
and	O
slow	O
waves	O
mixed	O
with	O
multifocal	O
spikes	B-Algorithm
alternating	O
with	O
almost	O
flat	O
suppression	O
phases	O
.	O
</s>
<s>
Unlike	O
LGS	O
,	O
the	O
spike-and-wave	B-Algorithm
pattern	O
is	O
consistent	O
during	O
both	O
waking	O
and	O
sleeping	O
states	O
.	O
</s>
<s>
In	O
continuous	O
spike-and-wave	B-Algorithm
syndrome	O
(	O
CSWS	O
)	O
,	O
a	O
rare	O
form	O
of	O
age-related	O
epilepsy	O
,	O
children	O
between	O
the	O
ages	O
of	O
three	O
and	O
seven	O
exhibit	O
continuous	O
spike-and-wave	B-Algorithm
discharges	O
during	O
slow-sleep	O
.	O
</s>
<s>
Spike-and-wave	B-Algorithm
activity	O
occupies	O
about	O
85%	O
of	O
the	O
non-rapid	O
eye	O
movement	O
sleep	O
.	O
</s>
<s>
This	O
continuous	O
pattern	O
during	O
sleep	O
,	O
like	O
other	O
aspects	O
of	O
spike-and-wave	B-Algorithm
activity	O
,	O
are	O
not	O
completely	O
understood	O
either	O
.	O
</s>
<s>
AEDs	O
aim	O
to	O
slow	O
down	O
the	O
excess	O
firing	O
,	O
associated	O
with	O
spike-and-wave	B-Algorithm
discharges	O
,	O
at	O
the	O
beginning	O
of	O
seizures	O
.	O
</s>
