<s>
The	O
P3b	B-Algorithm
is	O
a	O
subcomponent	O
of	O
the	O
P300	B-Algorithm
,	O
an	O
event-related	B-Algorithm
potential	I-Algorithm
(	O
ERP	O
)	O
component	O
that	O
can	O
be	O
observed	O
in	O
human	O
scalp	O
recordings	O
of	O
brain	O
electrical	O
activity	O
.	O
</s>
<s>
The	O
P3b	B-Algorithm
is	O
a	O
positive-going	O
amplitude	B-Application
(	O
usually	O
relative	O
to	O
a	O
reference	O
behind	O
the	O
ear	O
or	O
the	O
average	O
of	O
two	O
such	O
references	O
)	O
peaking	O
at	O
around	O
300	O
ms	O
,	O
though	O
the	O
peak	O
will	O
vary	O
in	O
latency	O
(	O
delay	O
between	O
stimulus	O
and	O
response	O
)	O
from	O
250	O
to	O
500	O
ms	O
or	O
later	O
depending	O
upon	O
the	O
task	O
and	O
on	O
the	O
individual	O
subject	O
response	O
.	O
</s>
<s>
Amplitudes	B-Application
are	O
typically	O
highest	O
on	O
the	O
scalp	O
over	O
parietal	O
brain	O
areas	O
.	O
</s>
<s>
The	O
P3b	B-Algorithm
has	O
been	O
a	O
prominent	O
tool	O
used	O
to	O
study	O
cognitive	O
processes	O
for	O
several	O
decades	O
.	O
</s>
<s>
Generally	O
speaking	O
,	O
improbable	O
events	O
will	O
elicit	O
a	O
P3b	B-Algorithm
,	O
and	O
the	O
less	O
probable	O
the	O
event	O
,	O
the	O
larger	O
the	O
P3b	B-Algorithm
.	O
</s>
<s>
However	O
,	O
in	O
order	O
to	O
elicit	O
a	O
P3b	B-Algorithm
,	O
the	O
improbable	O
event	O
must	O
be	O
related	O
to	O
the	O
task	O
at	O
hand	O
in	O
some	O
way	O
(	O
for	O
example	O
,	O
the	O
improbable	O
event	O
could	O
be	O
an	O
infrequent	O
target	O
letter	O
in	O
a	O
stream	O
of	O
letters	O
,	O
to	O
which	O
a	O
subject	O
might	O
respond	O
with	O
a	O
button	O
press	O
)	O
.	O
</s>
<s>
The	O
P3b	B-Algorithm
can	O
also	O
be	O
used	O
to	O
measure	O
how	O
demanding	O
a	O
task	O
is	O
on	O
cognitive	O
workload	O
.	O
</s>
<s>
Early	O
observations	O
of	O
the	O
P3b	B-Algorithm
were	O
reported	O
in	O
the	O
mid-1960s	O
.	O
</s>
<s>
When	O
examining	O
evoked	O
potentials	O
to	O
these	O
stimuli	O
(	O
i.e.	O
,	O
ERPs	O
)	O
,	O
Chapman	O
and	O
Bragdon	O
found	O
that	O
both	O
the	O
numbers	O
and	O
the	O
flashes	O
elicited	O
the	O
expected	O
sensory	O
responses	O
(	O
e.g.	O
,	O
visual	B-Algorithm
N1	I-Algorithm
components	O
)	O
,	O
and	O
that	O
the	O
amplitude	B-Application
of	O
these	O
responses	O
varied	O
in	O
an	O
expected	O
fashion	O
with	O
the	O
intensity	O
of	O
the	O
stimuli	O
.	O
</s>
<s>
They	O
also	O
noted	O
that	O
the	O
amplitude	B-Application
of	O
this	O
positivity	O
was	O
not	O
affected	O
by	O
the	O
intensity	O
of	O
the	O
stimulus	O
.	O
</s>
<s>
Chapman	O
and	O
Bragdon	O
speculated	O
that	O
this	O
differential	O
response	O
to	O
the	O
numbers	O
,	O
which	O
came	O
to	O
be	O
known	O
as	O
the	O
P300	B-Algorithm
response	O
,	O
resulted	O
from	O
the	O
fact	O
that	O
the	O
numbers	O
were	O
meaningful	O
to	O
the	O
participants	O
,	O
based	O
on	O
the	O
task	O
that	O
they	O
were	O
asked	O
to	O
perform	O
.	O
</s>
<s>
They	O
found	O
that	O
when	O
subjects	O
were	O
required	O
to	O
guess	O
what	O
the	O
following	O
stimulus	O
would	O
be	O
,	O
the	O
amplitude	B-Application
of	O
the	O
"	O
late	B-Algorithm
positive	I-Algorithm
complex	I-Algorithm
"	O
was	O
larger	O
than	O
when	O
they	O
knew	O
what	O
the	O
stimulus	O
would	O
be	O
.	O
</s>
<s>
They	O
found	O
that	O
the	O
amplitude	B-Application
of	O
the	O
positive	O
complex	O
was	O
larger	O
in	O
response	O
to	O
the	O
less	O
probable	O
stimuli	O
,	O
or	O
the	O
one	O
that	O
only	O
had	O
a	O
1	O
in	O
3	O
chance	O
of	O
appearing	O
.	O
</s>
<s>
Another	O
important	O
finding	O
from	O
these	O
studies	O
is	O
that	O
this	O
late	B-Algorithm
positive	I-Algorithm
complex	I-Algorithm
was	O
observed	O
for	O
both	O
the	O
clicks	O
and	O
flashes	O
,	O
indicating	O
that	O
the	O
physical	O
type	O
of	O
the	O
stimulus	O
(	O
auditory	O
or	O
visual	O
)	O
did	O
not	O
matter	O
.	O
</s>
<s>
This	O
shows	O
two	O
important	O
findings	O
:	O
first	O
that	O
this	O
late	O
positivity	O
occurred	O
when	O
the	O
uncertainty	O
about	O
the	O
type	O
of	O
click	O
was	O
resolved	O
,	O
and	O
second	O
that	O
even	O
an	O
absence	O
of	O
a	O
stimulus	O
,	O
when	O
it	O
was	O
relevant	O
to	O
the	O
task	O
,	O
would	O
elicit	O
the	O
late	B-Algorithm
positive	I-Algorithm
complex	I-Algorithm
.	O
</s>
<s>
These	O
early	O
studies	O
encouraged	O
the	O
use	O
of	O
ERP	O
methods	O
to	O
study	O
cognition	O
and	O
provided	O
a	O
foundation	O
for	O
the	O
extensive	O
work	O
on	O
the	O
P3b	B-Algorithm
in	O
the	O
decades	O
that	O
followed	O
.	O
</s>
<s>
Since	O
the	O
initial	O
discovery	O
of	O
this	O
ERP	O
component	O
,	O
research	O
has	O
shown	O
that	O
the	O
P300	B-Algorithm
is	O
not	O
a	O
unitary	O
phenomenon	O
.	O
</s>
<s>
Rather	O
,	O
we	O
can	O
distinguish	O
between	O
two	O
subcomponents	O
of	O
the	O
P300	B-Algorithm
:	O
the	O
novelty	O
P3	O
,	O
or	O
P3a	B-Algorithm
,	O
and	O
the	O
classic	O
P3	O
,	O
or	O
P3b	B-Algorithm
.	O
</s>
<s>
This	O
article	O
focuses	O
on	O
the	O
P3b	B-Algorithm
.	O
</s>
<s>
Assuming	O
that	O
a	O
cephalic	O
reference	O
is	O
used	O
(	O
i.e.	O
,	O
a	O
reference	O
electrode	O
placed	O
somewhere	O
on	O
the	O
head	O
,	O
such	O
as	O
the	O
tip	O
of	O
the	O
nose	O
or	O
the	O
chin	O
)	O
,	O
the	O
P3b	B-Algorithm
is	O
a	O
positive-going	O
ERP	O
whose	O
latency	O
at	O
peak	O
amplitude	B-Application
is	O
usually	O
about	O
300	O
ms	O
to	O
simple	O
sensory	O
stimuli	O
.	O
</s>
<s>
Amplitude	B-Application
has	O
been	O
defined	O
as	O
the	O
difference	O
between	O
the	O
mean	O
pre-stimulus	O
baseline	O
voltage	O
and	O
the	O
voltage	O
of	O
the	O
largest	O
(	O
in	O
this	O
case	O
,	O
positive-going	O
)	O
peak	O
of	O
the	O
ERP	O
waveform	O
in	O
a	O
specific	O
time	O
window	O
.	O
</s>
<s>
P3b	B-Algorithm
amplitude	B-Application
is	O
generally	O
relatively	O
large	O
(	O
10	O
–	O
20	O
microvolts	O
)	O
,	O
but	O
varies	O
systematically	O
as	O
a	O
function	O
of	O
a	O
number	O
of	O
important	O
factors	O
(	O
see	O
Functional	O
significance	O
:	O
Factors	O
that	O
influence	O
amplitude	B-Application
)	O
.	O
</s>
<s>
Latency	O
has	O
been	O
defined	O
as	O
the	O
time	O
from	O
the	O
onset	O
of	O
the	O
stimulus	O
(	O
or	O
whatever	O
the	O
desired	O
point	O
of	O
measurement	O
might	O
be	O
)	O
to	O
the	O
point	O
of	O
maximum	O
amplitude	B-Application
.	O
</s>
<s>
The	O
latency	O
of	O
the	O
P3b	B-Algorithm
is	O
usually	O
around	O
300	O
ms	O
,	O
though	O
this	O
can	O
vary	O
within	O
a	O
time	O
window	O
of	O
around	O
250	O
–	O
500	O
ms	O
(	O
or	O
later	O
)	O
depending	O
on	O
factors	O
such	O
as	O
task	O
conditions	O
and	O
the	O
age	B-Operating_System
of	O
the	O
subjects	O
(	O
see	O
Functional	O
significance	O
:	O
Factors	O
influence	O
latency	O
)	O
.	O
</s>
<s>
The	O
scalp	O
distribution	O
of	O
P3b	B-Algorithm
is	O
generally	O
larger	O
over	O
parietal	O
areas	O
.	O
</s>
<s>
However	O
,	O
using	O
a	O
15-electrode	O
setup	O
with	O
a	O
linked-earlobe	O
reference	O
and	O
an	O
oddball	B-Algorithm
task	I-Algorithm
(	O
described	O
below	O
)	O
,	O
researchers	O
have	O
also	O
found	O
that	O
the	O
positivity	O
increased	O
moving	O
from	O
frontal	O
to	O
parietal	O
sites	O
,	O
and	O
that	O
females	O
have	O
a	O
greater	O
increase	O
than	O
males	O
.	O
</s>
<s>
Other	O
research	O
,	O
using	O
the	O
International	O
10-20	O
System	O
with	O
a	O
left	O
mastoid	O
reference	O
and	O
an	O
oddball	B-Algorithm
task	I-Algorithm
,	O
has	O
shown	O
that	O
with	O
increasing	O
age	B-Operating_System
,	O
the	O
distribution	O
of	O
P3b	B-Algorithm
tends	O
to	O
shift	O
more	O
frontally	O
.	O
</s>
<s>
Thus	O
,	O
the	O
exact	O
distribution	O
may	O
be	O
dependent	O
upon	O
the	O
task	O
,	O
as	O
well	O
as	O
the	O
gender	O
and	O
age	B-Operating_System
of	O
the	O
subjects	O
.	O
</s>
<s>
The	O
P3b	B-Algorithm
can	O
be	O
observed	O
in	O
a	O
variety	O
of	O
experimental	O
contexts	O
.	O
</s>
<s>
The	O
most	O
common	O
paradigms	O
will	O
either	O
present	O
infrequent	O
,	O
task-relevant	O
stimuli	O
as	O
a	O
way	O
to	O
elicit	O
a	O
P3b	B-Algorithm
,	O
or	O
they	O
will	O
employ	O
two	O
tasks	O
at	O
the	O
same	O
time	O
to	O
use	O
P3b	B-Algorithm
as	O
a	O
measure	O
of	O
cognitive	O
workload	O
.	O
</s>
<s>
Of	O
course	O
,	O
any	O
experimental	O
paradigm	O
in	O
which	O
participants	O
are	O
instructed	O
to	O
attend	O
to	O
and	O
evaluate	O
stimuli	O
should	O
elicit	O
a	O
P3b	B-Algorithm
component	O
,	O
including	O
selective	O
attention	O
tasks	O
,	O
explicit	O
memory	O
tasks	O
,	O
and	O
visual	O
search	O
tasks	O
(	O
for	O
thorough	O
reviews	O
of	O
experimental	O
paradigms	O
which	O
have	O
been	O
used	O
to	O
elicit	O
this	O
component	O
,	O
see	O
Kok	O
,	O
2001	O
and	O
Verleger	O
,	O
1997	O
)	O
.	O
</s>
<s>
Two	O
classic	O
paradigms	O
are	O
the	O
two-stimulus	O
oddball	B-Algorithm
task	I-Algorithm
and	O
the	O
three-stimulus	O
oddball	B-Algorithm
task	I-Algorithm
,	O
the	O
latter	O
of	O
which	O
is	O
used	O
to	O
examine	O
both	O
P3b	B-Algorithm
and	O
P3a	B-Algorithm
.	O
</s>
<s>
In	O
a	O
classic	O
two-stimulus	O
oddball	B-Algorithm
task	I-Algorithm
,	O
a	O
sequence	O
of	O
visual	O
stimuli	O
is	O
presented	O
.	O
</s>
<s>
The	O
P3b	B-Algorithm
is	O
typically	O
observed	O
around	O
300	O
ms	O
after	O
each	O
presentation	O
of	O
the	O
target	O
(	O
oddball	O
)	O
stimulus	O
.	O
</s>
<s>
A	O
three-stimulus	O
oddball	B-Algorithm
task	I-Algorithm
is	O
exactly	O
like	O
the	O
two-stimulus	O
oddball	B-Algorithm
task	I-Algorithm
,	O
except	O
that	O
in	O
addition	O
to	O
the	O
targets	O
and	O
standards	O
,	O
an	O
infrequent	O
,	O
deviant	O
stimulus	O
such	O
as	O
the	O
letter	O
"	O
D	O
"	O
will	O
appear	O
.	O
</s>
<s>
The	O
P3b	B-Algorithm
has	O
been	O
shown	O
to	O
respond	O
only	O
to	O
task-relevant	O
stimuli	O
,	O
or	O
the	O
targets	O
that	O
are	O
actively	O
being	O
searched	O
for	O
(	O
in	O
this	O
example	O
,	O
the	O
letter	O
T	O
)	O
.	O
</s>
<s>
Therefore	O
,	O
the	O
deviant	O
standard	O
"	O
D	O
"	O
will	O
not	O
elicit	O
a	O
strong	O
P3b	B-Algorithm
because	O
it	O
is	O
not	O
relevant	O
to	O
the	O
task	O
.	O
</s>
<s>
However	O
,	O
the	O
deviant	O
standard	O
will	O
still	O
elicit	O
an	O
earlier	O
,	O
positive-going	O
potential	O
that	O
is	O
usually	O
higher	O
over	O
frontal	O
sites	O
known	O
as	O
the	O
P3a	B-Algorithm
.	O
</s>
<s>
Unlike	O
the	O
P3b	B-Algorithm
,	O
the	O
P3a	B-Algorithm
will	O
habituate	O
with	O
repeated	O
presentations	O
.	O
</s>
<s>
Another	O
set	O
of	O
paradigms	O
used	O
to	O
study	O
the	O
P3b	B-Algorithm
are	O
dual	O
task	O
paradigms	O
.	O
</s>
<s>
Though	O
the	O
primary	O
task	O
can	O
be	O
of	O
virtually	O
any	O
type	O
,	O
the	O
secondary	O
task	O
should	O
involve	O
some	O
traditional	O
P300	B-Algorithm
paradigm	O
(	O
e.g.	O
,	O
an	O
oddball	B-Algorithm
task	I-Algorithm
)	O
.	O
</s>
<s>
When	O
these	O
tasks	O
are	O
performed	O
concurrently	O
,	O
we	O
would	O
expect	O
to	O
see	O
a	O
reduction	O
in	O
P3b	B-Algorithm
amplitude	B-Application
in	O
response	O
to	O
the	O
secondary	O
task	O
if	O
the	O
primary	O
task	O
requires	O
some	O
stimulus	O
evaluation	O
resources	O
.	O
</s>
<s>
In	O
fact	O
,	O
there	O
should	O
be	O
a	O
reciprocal	O
relationship	O
between	O
the	O
amplitudes	B-Application
of	O
the	O
P3b	B-Algorithm
response	O
elicited	O
by	O
the	O
primary	O
and	O
secondary	O
tasks	O
,	O
respectively	O
.	O
</s>
<s>
The	O
difficulty	O
of	O
the	O
primary	O
task	O
is	O
usually	O
manipulated	O
in	O
various	O
ways	O
,	O
and	O
the	O
impacts	O
of	O
these	O
manipulations	O
on	O
the	O
P3b	B-Algorithm
response	O
to	O
the	O
secondary	O
task	O
are	O
examined	O
.	O
</s>
<s>
A	O
motor	O
manipulation	O
like	O
this	O
will	O
typically	O
impact	O
reaction	O
times	O
on	O
the	O
secondary	O
task	O
,	O
but	O
will	O
not	O
impact	O
the	O
P3b	B-Algorithm
response	O
.	O
</s>
<s>
However	O
,	O
if	O
you	O
increase	O
the	O
demand	O
on	O
working	O
memory	O
or	O
other	O
cognitive	O
resources	O
during	O
the	O
primary	O
task	O
,	O
for	O
example	O
by	O
adding	O
objects	O
to	O
the	O
screen	O
or	O
only	O
having	O
subjects	O
selectively	O
attend	O
to	O
one	O
part	O
of	O
the	O
screen	O
,	O
the	O
amplitude	B-Application
of	O
the	O
P3b	B-Algorithm
in	O
response	O
to	O
oddballs	O
in	O
the	O
secondary	O
task	O
will	O
diminish	O
.	O
</s>
<s>
The	O
amount	O
of	O
time	O
or	O
items	O
separating	O
the	O
two	O
targets	O
is	O
varied	O
,	O
and	O
the	O
amplitude	B-Application
of	O
the	O
P3b	B-Algorithm
in	O
response	O
to	O
the	O
second	O
item	O
is	O
examined	O
.	O
</s>
<s>
Diminished	O
amplitude	B-Application
of	O
the	O
P3b	B-Algorithm
response	O
to	O
the	O
second	O
target	O
would	O
be	O
expected	O
when	O
the	O
first	O
target	O
required	O
more	O
processing	O
or	O
working	O
memory	O
resources	O
.	O
</s>
<s>
Donchin	O
stated	O
that	O
the	O
less	O
probable	O
the	O
event	O
,	O
the	O
larger	O
the	O
P3b	B-Algorithm
amplitude	B-Application
will	O
be	O
.	O
</s>
<s>
There	O
are	O
several	O
types	O
of	O
probability	O
that	O
can	O
affect	O
P3b	B-Algorithm
amplitude	B-Application
:	O
global	O
probability	O
,	O
or	O
how	O
frequent	O
the	O
targets	O
are	O
relative	O
to	O
the	O
number	O
of	O
standards	O
(	O
for	O
example	O
,	O
P3b	B-Algorithm
amplitude	B-Application
is	O
greater	O
when	O
targets	O
make	O
up	O
10	O
percent	O
of	O
the	O
stimuli	O
than	O
when	O
targets	O
comprise	O
20	O
percent	O
of	O
the	O
stimuli	O
)	O
;	O
local	O
probability	O
,	O
or	O
the	O
probability	O
within	O
the	O
specific	O
sequence	O
of	O
the	O
events	O
(	O
for	O
example	O
,	O
whether	O
a	O
target	O
followed	O
a	O
standard	O
or	O
another	O
target	O
)	O
;	O
and	O
temporal	O
probability	O
,	O
or	O
how	O
frequently	O
targets	O
occur	O
within	O
a	O
one-minute	O
time	O
period	O
(	O
whether	O
standards	O
are	O
present	O
or	O
not	O
)	O
.	O
</s>
<s>
Ray	O
"	O
Skip	O
"	O
Johnson	O
,	O
Jr.	O
,	O
now	O
a	O
professor	O
at	O
Queens	O
College	O
,	O
published	O
a	O
triarchic	O
model	O
of	O
P300	B-Algorithm
amplitude	B-Application
in	O
1986	O
.	O
</s>
<s>
Although	O
he	O
does	O
not	O
explicitly	O
refer	O
to	O
P3b	B-Algorithm
in	O
this	O
paper	O
,	O
most	O
of	O
his	O
discussions	O
refer	O
to	O
P3b	B-Algorithm
.	O
</s>
<s>
He	O
offered	O
three	O
things	O
that	O
affected	O
the	O
amplitude	B-Application
–	O
subjective	O
probability	O
,	O
stimulus	O
meaning	O
,	O
and	O
information	O
transmission	O
.	O
</s>
<s>
He	O
summarized	O
his	O
view	O
in	O
the	O
following	O
formula	O
:	O
P300	B-Algorithm
amplitude	B-Application
=	O
f[ T	O
x	O
(	O
1/P	O
+	O
M	O
)	O
]	O
,	O
where	O
P	O
is	O
subjective	O
probability	O
,	O
M	O
is	O
stimulus	O
meaning	O
,	O
and	O
T	O
is	O
information	O
transmitted	O
.	O
</s>
<s>
He	O
describes	O
subjective	O
probability	O
as	O
objective	O
probability	O
with	O
the	O
added	O
element	O
of	O
human	O
judgment	O
of	O
how	O
relevant	O
a	O
stimulus	O
is	O
to	O
the	O
task	O
,	O
and	O
notes	O
that	O
P300	B-Algorithm
amplitude	B-Application
is	O
directly	O
related	O
to	O
the	O
amount	O
of	O
uncertainty	O
that	O
is	O
reduced	O
by	O
a	O
stimulus	O
.	O
</s>
<s>
A	O
closely	O
related	O
dependence	O
between	O
the	O
P300	B-Algorithm
and	O
subjective	O
probability	O
was	O
shown	O
by	O
Levi-Aharoni	O
et	O
al	O
.	O
</s>
<s>
who	O
used	O
a	O
fuzzy	O
,	O
compressed	O
representation	O
of	O
stimulus	O
probability	O
to	O
explain	O
the	O
single-trial	O
variability	O
in	O
the	O
P300	B-Algorithm
response	O
magnitude	O
.	O
</s>
<s>
However	O
,	O
it	O
has	O
also	O
been	O
found	O
that	O
P300	B-Algorithm
amplitude	B-Application
can	O
change	O
in	O
the	O
absence	O
of	O
changes	O
in	O
probability	O
.	O
</s>
<s>
Stimulus	O
meaning	O
encompasses	O
three	O
independent	O
variables	O
that	O
can	O
be	O
manipulated	O
–	O
task	O
complexity	O
(	O
how	O
difficult	O
a	O
task	O
is	O
,	O
or	O
how	O
many	O
tasks	O
must	O
be	O
performed	O
at	O
once	O
)	O
,	O
stimulus	O
complexity	O
(	O
perceptual	O
demand	O
,	O
or	O
how	O
many	O
relevant	O
features	O
of	O
the	O
stimulus	O
must	O
be	O
processed	O
–	O
a	O
face	O
being	O
more	O
complex	O
than	O
a	O
dot	O
)	O
,	O
and	O
stimulus	O
value	O
(	O
the	O
significance	O
,	O
or	O
for	O
example	O
the	O
monetary	O
value	O
:	O
the	O
greater	O
the	O
value	O
the	O
larger	O
the	O
P300	B-Algorithm
amplitude	B-Application
)	O
.	O
</s>
<s>
When	O
much	O
information	O
is	O
lost	O
for	O
external	O
reasons	O
,	O
for	O
example	O
because	O
the	O
stimulus	O
is	O
harder	O
to	O
discriminate	O
or	O
perceive	O
,	O
P300	B-Algorithm
amplitude	B-Application
is	O
lower	O
.	O
</s>
<s>
P3b	B-Algorithm
requires	O
attention	O
,	O
and	O
increasing	O
the	O
difficulty	O
of	O
maintaining	O
attention	O
will	O
correspondingly	O
decrease	O
P3b	B-Algorithm
amplitude	B-Application
.	O
</s>
<s>
To	O
summarize	O
,	O
Johnson	O
describes	O
that	O
probability	O
on	O
many	O
levels	O
,	O
the	O
relevance	O
of	O
the	O
stimulus	O
to	O
the	O
task	O
,	O
and	O
the	O
amount	O
information	O
a	O
stimulus	O
transmits	O
are	O
all	O
variables	O
that	O
will	O
determine	O
P3b	B-Algorithm
amplitude	B-Application
.	O
</s>
<s>
More	O
recently	O
,	O
Albert	O
Kok	O
reviewed	O
the	O
literature	O
on	O
cognitive	O
workload	O
,	O
and	O
concluded	O
that	O
P3b	B-Algorithm
amplitude	B-Application
depends	O
on	O
the	O
demands	O
on	O
cognitive	O
capacity	O
.	O
</s>
<s>
When	O
the	O
primary	O
task	O
is	O
more	O
perceptually	O
and	O
cognitively	O
demanding	O
,	O
the	O
P3b	B-Algorithm
amplitude	B-Application
in	O
response	O
to	O
oddballs	O
in	O
the	O
secondary	O
task	O
is	O
decreased	O
.	O
</s>
<s>
Kok	O
also	O
supports	O
aspects	O
of	O
Johnson	O
's	O
theory	O
,	O
stating	O
that	O
the	O
amount	O
of	O
attention	O
allocated	O
to	O
a	O
task	O
,	O
the	O
relevance	O
of	O
the	O
stimulus	O
to	O
the	O
task	O
,	O
and	O
the	O
probability	O
of	O
the	O
stimulus	O
will	O
all	O
help	O
determine	O
what	O
the	O
P3b	B-Algorithm
amplitude	B-Application
will	O
be	O
.	O
</s>
<s>
Consistently	O
with	O
the	O
models	O
by	O
Johnson	O
and	O
Kok	O
,	O
a	O
model	O
of	O
the	O
P300	B-Algorithm
response	O
magnitude	O
was	O
proposed	O
by	O
Levi-Aharoni	O
,	O
Shriki	O
and	O
Tishby	O
,	O
based	O
on	O
the	O
Information	B-General_Concept
Bottleneck	I-General_Concept
framework	O
and	O
a	O
prediction-error	O
model	O
by	O
Rubin	O
et	O
al	O
.	O
</s>
<s>
Their	O
results	O
show	O
that	O
the	O
single-trial	O
variability	O
in	O
the	O
P300	B-Algorithm
response	O
magnitude	O
can	O
be	O
explained	O
by	O
a	O
subjective	O
surprise	O
that	O
is	O
constructed	O
from	O
compressed	O
probability	O
representations	O
,	O
dependent	O
on	O
the	O
memory	O
capacity	O
allocated	O
to	O
the	O
task	O
and	O
on	O
the	O
relevant	O
features	O
of	O
preceding	O
stimuli	O
for	O
predicting	O
the	O
upcoming	O
stimulus	O
.	O
</s>
<s>
Furthermore	O
,	O
based	O
on	O
this	O
dependency	O
they	O
proposed	O
a	O
method	O
to	O
utilize	O
the	O
individual	O
P300	B-Algorithm
response	O
to	O
obtain	O
an	O
estimate	O
of	O
individual	O
recent	O
memory	O
capacity	O
.	O
</s>
<s>
Other	O
variables	O
have	O
been	O
found	O
to	O
influence	O
P3b	B-Algorithm
amplitude	B-Application
.	O
</s>
<s>
Some	O
research	O
using	O
oddball	B-Algorithm
tasks	I-Algorithm
has	O
indicated	O
that	O
females	O
have	O
larger	O
P3b	B-Algorithm
amplitudes	B-Application
than	O
males	O
,	O
and	O
that	O
the	O
amplitude	B-Application
increases	O
more	O
moving	O
from	O
frontal	O
to	O
parietal	O
areas	O
.	O
</s>
<s>
Other	O
research	O
has	O
found	O
that	O
learning	O
in	O
a	O
topic	O
area	O
can	O
affect	O
P3b	B-Algorithm
amplitude	B-Application
in	O
tasks	O
related	O
to	O
that	O
area	O
.	O
</s>
<s>
Researchers	O
found	O
that	O
those	O
who	O
had	O
received	O
prior	O
training	O
had	O
greater	O
P3b	B-Algorithm
amplitudes	B-Application
in	O
response	O
to	O
harmonic	O
violations	O
in	O
musical	O
sequences	O
.	O
</s>
<s>
There	O
is	O
also	O
some	O
evidence	O
to	O
suggest	O
that	O
in	O
all	O
subjects	O
,	O
P3b	B-Algorithm
amplitude	B-Application
is	O
distributed	O
asymmetrically	O
over	O
the	O
scalp	O
.	O
</s>
<s>
Research	O
has	O
shown	O
that	O
P3b	B-Algorithm
amplitudes	B-Application
are	O
systematically	O
larger	O
over	O
the	O
right	O
frontal	O
and	O
central	O
hemispheres	O
than	O
the	O
left	O
,	O
though	O
there	O
is	O
some	O
debate	O
as	O
to	O
whether	O
this	O
is	O
due	O
to	O
structural	O
causes	O
(	O
such	O
as	O
skull	O
thickness	O
or	O
cranial	O
irregularities	O
)	O
or	O
to	O
cognitive	O
causes	O
.	O
</s>
<s>
A	O
number	O
of	O
clinical	O
variables	O
such	O
as	O
age	B-Operating_System
,	O
disease	O
,	O
mental	O
illness	O
,	O
and	O
substance	O
use	O
have	O
been	O
studied	O
in	O
relation	O
to	O
P3b	B-Algorithm
amplitude	B-Application
.	O
</s>
<s>
Many	O
of	O
these	O
studies	O
do	O
not	O
refer	O
to	O
the	O
P3b	B-Algorithm
explicitly	O
,	O
but	O
most	O
use	O
oddball	B-Algorithm
tasks	I-Algorithm
and	O
thus	O
would	O
most	O
likely	O
have	O
elicited	O
a	O
P3b	B-Algorithm
.	O
</s>
<s>
As	O
previously	O
noted	O
,	O
the	O
topography	O
of	O
the	O
amplitude	B-Application
of	O
P3b	B-Algorithm
tends	O
to	O
shift	O
more	O
frontally	O
with	O
age	B-Operating_System
,	O
but	O
amplitude	B-Application
in	O
these	O
frontal	O
areas	O
does	O
not	O
seem	O
to	O
be	O
affected	O
by	O
age	B-Operating_System
.	O
</s>
<s>
Another	O
study	O
using	O
an	O
auditory	O
oddball	B-Algorithm
task	I-Algorithm
showed	O
that	O
P300	B-Algorithm
amplitude	B-Application
was	O
enlarged	O
in	O
unmedicated	O
individuals	O
with	O
mild	O
Parkinson	O
's	O
disease	O
when	O
compared	O
with	O
healthy	O
controls	O
.	O
</s>
<s>
The	O
same	O
study	O
also	O
used	O
older	O
and	O
younger	O
groups	O
of	O
individuals	O
with	O
Parkinson	O
's	O
disease	O
,	O
and	O
found	O
that	O
age	B-Operating_System
itself	O
did	O
not	O
have	O
an	O
effect	O
on	O
amplitude	B-Application
.	O
</s>
<s>
Other	O
studies	O
have	O
shown	O
that	O
individuals	O
with	O
schizophrenia	B-Application
have	O
a	O
marked	O
reduction	O
in	O
P3b	B-Algorithm
amplitude	B-Application
,	O
suggesting	O
impairments	O
in	O
working	O
memory	O
or	O
other	O
processing	O
.	O
</s>
<s>
Substance	O
use	O
has	O
also	O
been	O
shown	O
to	O
affect	O
P3b	B-Algorithm
.	O
</s>
<s>
Some	O
studies	O
show	O
that	O
alcoholics	O
have	O
larger	O
P300	B-Algorithm
amplitudes	B-Application
in	O
response	O
to	O
an	O
auditory	O
oddball	B-Algorithm
task	I-Algorithm
,	O
but	O
that	O
alcoholics	O
who	O
have	O
many	O
alcoholic	O
relatives	O
have	O
lower	O
P300	B-Algorithm
amplitudes	B-Application
when	O
compared	O
to	O
controls	O
.	O
</s>
<s>
This	O
tendency	O
for	O
P3b	B-Algorithm
amplitude	B-Application
to	O
be	O
weaker	O
for	O
those	O
with	O
a	O
family	O
history	O
of	O
alcoholism	O
may	O
be	O
more	O
general	O
,	O
in	O
that	O
other	O
substance	O
use	O
disorders	O
and	O
related	O
psychiatric	O
disorders	O
show	O
the	O
same	O
reduction	O
,	O
often	O
before	O
the	O
substance	O
use	O
was	O
initiated	O
.	O
</s>
<s>
This	O
particular	O
reduction	O
in	O
P3b	B-Algorithm
amplitude	B-Application
may	O
be	O
due	O
to	O
weak	O
neuromodulatory	O
factors	O
in	O
the	O
brains	O
of	O
those	O
liable	O
to	O
develop	O
substance	O
use	O
problems	O
.	O
</s>
<s>
P300	B-Algorithm
amplitude	B-Application
also	O
appears	O
to	O
be	O
sensitive	O
to	O
pharmacological	O
interventions	O
.	O
</s>
<s>
When	O
twelve	O
healthy	O
subjects	O
were	O
given	O
lorazepam	O
(	O
a	O
benzodiazepine	O
drug	O
used	O
to	O
treat	O
anxiety	O
and	O
sometimes	O
depression	O
)	O
and	O
asked	O
to	O
perform	O
an	O
oddball	B-Algorithm
task	I-Algorithm
,	O
their	O
P300	B-Algorithm
amplitude	B-Application
was	O
reduced	O
.	O
</s>
<s>
These	O
studies	O
and	O
others	O
have	O
shown	O
that	O
conditions	O
that	O
tend	O
to	O
influence	O
cognition	O
(	O
such	O
as	O
age	B-Operating_System
,	O
disease	O
,	O
mental	O
illness	O
,	O
and	O
substance	O
use	O
)	O
affect	O
the	O
amplitude	B-Application
of	O
P3b	B-Algorithm
or	O
its	O
distribution	O
.	O
</s>
<s>
In	O
line	O
with	O
the	O
view	O
that	O
the	O
P3b	B-Algorithm
component	O
reflects	O
uncertainty	O
resolution	O
,	O
there	O
is	O
evidence	O
to	O
suggest	O
that	O
time	O
at	O
which	O
this	O
component	O
begins	O
to	O
appear	O
in	O
the	O
ERP	O
(	O
i.e.	O
,	O
its	O
latency	O
)	O
corresponds	O
to	O
the	O
time	O
at	O
which	O
uncertainty	O
is	O
resolved	O
.	O
</s>
<s>
When	O
a	O
double	O
click	O
occurred	O
,	O
the	O
P3b	B-Algorithm
response	O
occurred	O
approximately	O
300	O
ms	O
after	O
the	O
second	O
click	O
.	O
</s>
<s>
More	O
importantly	O
,	O
the	O
timing	O
of	O
the	O
P3b	B-Algorithm
response	O
was	O
almost	O
identical	O
when	O
only	O
a	O
single	O
click	O
was	O
presented	O
,	O
suggesting	O
that	O
this	O
component	O
was	O
generated	O
based	O
upon	O
when	O
the	O
second	O
click	O
might	O
have	O
occurred	O
.	O
</s>
<s>
In	O
fact	O
,	O
when	O
the	O
duration	O
between	O
the	O
two	O
clicks	O
was	O
manipulated	O
,	O
the	O
onset	O
of	O
the	O
P3b	B-Algorithm
was	O
delayed	O
by	O
the	O
exact	O
amount	O
of	O
time	O
between	O
them	O
(	O
e.g.	O
,	O
when	O
the	O
second	O
click	O
was	O
presented	O
500	O
ms	O
after	O
the	O
first	O
one	O
,	O
the	O
P3b	B-Algorithm
response	O
occurred	O
at	O
800	O
ms	O
)	O
.	O
</s>
<s>
In	O
contrast	O
,	O
when	O
participants	O
were	O
instructed	O
to	O
respond	O
based	O
upon	O
the	O
intensity	O
of	O
the	O
clicks	O
,	O
the	O
P3b	B-Algorithm
response	O
always	O
occurred	O
approximately	O
300	O
ms	O
after	O
the	O
first	O
click	O
.	O
</s>
<s>
If	O
in	O
fact	O
the	O
latency	O
of	O
the	O
P3b	B-Algorithm
component	O
reflects	O
the	O
timing	O
of	O
uncertainty	O
resolution	O
,	O
then	O
one	O
might	O
expect	O
the	O
latency	O
of	O
this	O
component	O
to	O
be	O
closely	O
related	O
to	O
the	O
difficulty	O
of	O
the	O
evaluation	O
or	O
categorization	O
.	O
</s>
<s>
McCarthy	O
and	O
Donchin	O
found	O
that	O
the	O
P3b	B-Algorithm
component	O
occurred	O
significantly	O
earlier	O
when	O
the	O
rest	O
of	O
the	O
items	O
in	O
the	O
matrix	O
were	O
number	O
signs	O
( #	O
)	O
,	O
relative	O
to	O
when	O
the	O
rest	O
of	O
the	O
items	O
were	O
random	O
letters	O
.	O
</s>
<s>
Along	O
these	O
same	O
lines	O
,	O
several	O
other	O
task	O
manipulations	O
which	O
are	O
thought	O
to	O
influence	O
the	O
difficulty	O
of	O
the	O
evaluation	O
or	O
categorization	O
involved	O
have	O
been	O
found	O
to	O
influence	O
P3b	B-Algorithm
latency	O
(	O
e.g.	O
,	O
decreasing	O
the	O
physical	O
intensity	O
of	O
the	O
stimuli	O
;	O
see	O
Verleger	O
,	O
1997	O
for	O
a	O
review	O
)	O
.	O
</s>
<s>
Collectively	O
,	O
these	O
findings	O
suggest	O
that	O
P3b	B-Algorithm
latency	O
reflects	O
the	O
amount	O
of	O
time	O
it	O
takes	O
participants	O
to	O
evaluate	O
or	O
categorize	O
the	O
stimulus	O
in	O
question	O
.	O
</s>
<s>
Given	O
that	O
performance	O
indices	O
(	O
such	O
as	O
response	O
times	O
)	O
have	O
long	O
been	O
used	O
in	O
cognitive	O
psychology	O
to	O
study	O
the	O
duration	O
and/or	O
timing	O
of	O
mental	O
events	O
,	O
one	O
might	O
ask	O
whether	O
P3b	B-Algorithm
latency	O
simply	O
provides	O
a	O
comparable	O
neural	O
index	O
of	O
these	O
same	O
processes	O
.	O
</s>
<s>
Research	O
suggests	O
that	O
P3b	B-Algorithm
latency	O
is	O
highly	O
correlated	O
with	O
response	O
times	O
when	O
participants	O
are	O
instructed	O
to	O
prioritize	O
accuracy	O
in	O
their	O
responses	O
,	O
but	O
is	O
less	O
correlated	O
with	O
response	O
times	O
when	O
participants	O
are	O
instructed	O
to	O
prioritize	O
speed	O
in	O
their	O
responses	O
.	O
</s>
<s>
This	O
pattern	O
of	O
results	O
suggests	O
that	O
the	O
P3b	B-Algorithm
primary	O
reflects	O
stimulus	O
evaluation	O
processes	O
,	O
whereas	O
response	O
times	O
are	O
thought	O
to	O
reflect	O
both	O
stimulus	O
evaluation	O
and	O
response	O
selection	O
(	O
but	O
for	O
a	O
critique	O
of	O
this	O
claim	O
,	O
see	O
Verleger	O
,	O
1997	O
)	O
.	O
</s>
<s>
Additional	O
support	O
for	O
this	O
conclusion	O
comes	O
from	O
the	O
finding	O
that	O
P3b	B-Algorithm
latency	O
is	O
not	O
affected	O
by	O
experimental	O
manipulations	O
thought	O
to	O
influence	O
response	O
selection	O
processes	O
(	O
e.g.	O
,	O
stimulus-response	O
compatibility	O
)	O
,	O
whereas	O
reaction	O
times	O
are	O
(	O
e.g.	O
,	O
McCarthy	O
&	O
Donchin	O
,	O
1981	O
)	O
.	O
</s>
<s>
An	O
important	O
implication	O
of	O
this	O
conclusion	O
is	O
that	O
the	O
P3b	B-Algorithm
component	O
can	O
used	O
to	O
identify	O
the	O
"	O
locus	O
of	O
interference	O
"	O
in	O
many	O
popular	O
cognitive	O
paradigms	O
.	O
</s>
<s>
For	O
example	O
,	O
Luck	O
(	O
1998	O
)	O
found	O
that	O
P3b	B-Algorithm
latency	O
was	O
only	O
slightly	O
delayed	O
during	O
the	O
psychological	O
refractory	O
period	O
(	O
PRP	O
)	O
,	O
suggesting	O
that	O
response	O
time	O
interference	O
in	O
this	O
paradigm	O
primarily	O
reflects	O
a	O
delay	O
in	O
response	O
selection	O
.	O
</s>
<s>
Other	O
factors	O
which	O
have	O
been	O
found	O
to	O
influence	O
the	O
latency	O
of	O
the	O
P3b	B-Algorithm
response	O
include	O
factors	O
related	O
to	O
physiological	O
arousal	O
,	O
such	O
as	O
heart	O
rate	O
and	O
caffeine	B-Application
consumption	O
,	O
as	O
well	O
as	O
factors	O
related	O
to	O
cognitive	O
capacity	O
,	O
such	O
as	O
age	B-Operating_System
and	O
differences	O
in	O
how	O
rapidly	O
individuals	O
can	O
allocate	O
attentional	O
resources	O
.	O
</s>
<s>
Several	O
theories	O
have	O
been	O
put	O
forward	O
about	O
what	O
cognitive	O
processes	O
the	O
P3b	B-Algorithm
reflects	O
.	O
</s>
<s>
A	O
P300	B-Algorithm
wave	O
,	O
including	O
a	O
P3b	B-Algorithm
,	O
is	O
generated	O
when	O
the	O
brain	O
receives	O
information	O
that	O
indicates	O
that	O
it	O
needs	O
to	O
change	O
these	O
hypotheses	O
,	O
or	O
update	O
its	O
mental	O
model	O
of	O
the	O
world	O
.	O
</s>
<s>
In	O
other	O
words	O
,	O
a	O
P300	B-Algorithm
is	O
elicited	O
whenever	O
there	O
is	O
sufficient	O
information	O
to	O
indicate	O
that	O
the	O
brain	O
needs	O
to	O
update	O
working	O
memory	O
.	O
</s>
<s>
For	O
example	O
,	O
Verleger	O
and	O
colleagues	O
(	O
2005	O
)	O
have	O
proposed	O
that	O
the	O
P3b	B-Algorithm
component	O
reflects	O
a	O
process	O
that	O
mediates	O
between	O
perceptual	O
analysis	O
and	O
response	O
initiation	O
.	O
</s>
<s>
This	O
theory	O
constitutes	O
a	O
direct	O
challenge	O
to	O
the	O
widely	O
held	O
view	O
that	O
the	O
P3b	B-Algorithm
component	O
reflects	O
processes	O
involved	O
in	O
perception	O
but	O
not	O
response	O
initiation	O
(	O
see	O
Verleger	O
,	O
1997	O
)	O
.	O
</s>
<s>
Another	O
theory	O
proposed	O
by	O
Kok	O
proposed	O
that	O
the	O
P3b	B-Algorithm
reflects	O
mechanisms	O
involved	O
in	O
event	O
categorization	O
,	O
or	O
the	O
process	O
that	O
leads	O
to	O
the	O
decision	O
about	O
whether	O
an	O
external	O
stimulus	O
matches	O
or	O
does	O
not	O
match	O
an	O
internal	O
representation	O
of	O
a	O
specific	O
category	O
or	O
stimulus	O
.	O
</s>
<s>
Categorization	O
requires	O
processes	O
such	O
as	O
attention	O
,	O
perception	O
,	O
and	O
working	O
memory	O
,	O
all	O
of	O
which	O
are	O
known	O
to	O
affect	O
P3b	B-Algorithm
amplitude	B-Application
(	O
as	O
reviewed	O
above	O
)	O
,	O
and	O
thus	O
this	O
model	O
integrates	O
the	O
research	O
findings	O
on	O
P3b	B-Algorithm
.	O
</s>
<s>
Kok	O
also	O
discusses	O
another	O
"	O
template-matching	O
model	O
"	O
,	O
where	O
subjects	O
are	O
required	O
to	O
detect	O
a	O
target	O
and	O
create	O
a	O
representation	O
or	O
"	O
template	O
"	O
of	O
the	O
stimulus	O
,	O
and	O
the	O
P3b	B-Algorithm
is	O
strongest	O
when	O
the	O
template	O
is	O
matched	O
by	O
presented	O
stimuli	O
.	O
</s>
<s>
The	O
template-matching	O
model	O
is	O
similar	O
to	O
the	O
event	O
categorization	O
model	O
,	O
and	O
suggests	O
that	O
the	O
P3b	B-Algorithm
reflects	O
processes	O
that	O
underlie	O
recognition	O
memory	O
(	O
which	O
can	O
also	O
require	O
working	O
memory	O
.	O
)	O
</s>
<s>
The	O
cognitive	O
version	O
of	O
Verleger	O
's	O
model	O
suggests	O
that	O
the	O
P3b	B-Algorithm
is	O
generated	O
when	O
a	O
decision	O
is	O
made	O
that	O
a	O
stimulus	O
belongs	O
to	O
a	O
task-relevant	O
category	O
.	O
</s>
<s>
As	O
Kok	O
summarizes	O
,	O
P3b	B-Algorithm
appears	O
to	O
integrate	O
processes	O
that	O
are	O
required	O
to	O
identify	O
and	O
match	O
a	O
stimulus	O
with	O
some	O
kind	O
of	O
internal	O
representation	O
.	O
</s>
<s>
The	O
neural	O
generators	O
of	O
the	O
P3b	B-Algorithm
are	O
highly	O
debated	O
.	O
</s>
<s>
Early	O
studies	O
using	O
electrodes	O
implanted	O
in	O
the	O
brain	O
indicated	O
that	O
the	O
hippocampal	O
formation	O
might	O
generate	O
the	O
P300	B-Algorithm
.	O
</s>
<s>
However	O
,	O
later	O
work	O
found	O
that	O
if	O
the	O
hippocampus	O
is	O
lesioned	O
or	O
damaged	O
,	O
the	O
P300	B-Algorithm
is	O
still	O
generated	O
and	O
no	O
reliable	O
differences	O
in	O
its	O
amplitude	B-Application
or	O
latency	O
are	O
observed	O
.	O
</s>
<s>
Subsequent	O
research	O
found	O
that	O
lesioning	O
the	O
temporal-parietal	O
lobe	O
junction	O
significantly	O
affected	O
P300	B-Algorithm
production	O
,	O
indicating	O
that	O
this	O
area	O
may	O
contain	O
one	O
or	O
more	O
generators	O
of	O
the	O
P3b	B-Algorithm
.	O
</s>
<s>
This	O
suggests	O
that	O
the	O
P3b	B-Algorithm
might	O
indicate	O
some	O
kind	O
of	O
circuit	O
pathway	O
between	O
frontal	O
and	O
temporal/parietal	O
brain	O
areas	O
.	O
</s>
<s>
A	O
temporal-parietal	O
generator	O
would	O
be	O
logical	O
,	O
because	O
P3b	B-Algorithm
appears	O
to	O
be	O
elicited	O
when	O
attentional	O
resource	O
activations	O
promote	O
working	O
memory	O
and	O
other	O
processes	O
in	O
temporal-parietal	O
areas	O
.	O
</s>
<s>
Further	O
EEG	O
research	O
utilizing	O
source	O
modeling	O
techniques	O
,	O
along	O
with	O
research	O
using	O
alternative	O
brain	O
imaging	O
methods	O
(	O
e.g.	O
,	O
fMRI	O
,	O
MEG	O
)	O
,	O
intracranial	O
recordings	O
,	O
and	O
brain	O
injury	O
patients	O
,	O
has	O
also	O
indicated	O
that	O
the	O
P3b	B-Algorithm
component	O
originates	O
from	O
activation	O
in	O
the	O
parietal	O
and	O
temporal	O
lobes	O
of	O
the	O
cerebral	O
cortex	O
.	O
</s>
<s>
There	O
is	O
also	O
some	O
evidence	O
that	O
activation	O
is	O
certain	O
limbic	O
structures	O
,	O
such	O
as	O
the	O
anterior	O
cingulate	O
cortex	O
,	O
may	O
contribute	O
to	O
the	O
P3b	B-Algorithm
component	O
.	O
</s>
<s>
It	O
is	O
not	O
yet	O
known	O
which	O
neurotransmitter	O
systems	O
are	O
responsible	O
for	O
the	O
generation	O
of	O
P3b	B-Algorithm
.	O
</s>
<s>
The	O
temporal-parietal	O
region	O
is	O
densely	O
populated	O
by	O
norepenepherine	O
inputs	O
,	O
and	O
there	O
is	O
some	O
evidence	O
that	O
the	O
locus	O
coeruleus	O
norepinephrine	O
system	O
might	O
be	O
responsible	O
for	O
generating	O
the	O
P3b	B-Algorithm
.	O
</s>
<s>
Because	O
many	O
of	O
these	O
studies	O
were	O
conducted	O
using	O
animals	O
,	O
further	O
research	O
is	O
needed	O
to	O
determine	O
the	O
neurotransmitters	O
that	O
are	O
responsible	O
for	O
P3b	B-Algorithm
generation	O
.	O
</s>
