<s>
In	O
electroencephalography	B-Application
,	O
the	O
P50	B-Algorithm
is	O
an	O
event	B-Algorithm
related	I-Algorithm
potential	I-Algorithm
occurring	O
approximately	O
50	O
ms	O
after	O
the	O
presentation	O
of	O
a	O
stimulus	O
,	O
usually	O
an	O
auditory	O
click	O
.	O
</s>
<s>
The	O
P50	B-Algorithm
response	O
is	O
used	O
to	O
measure	O
sensory	O
gating	O
,	O
or	O
the	O
reduced	O
neurophysiological	O
response	O
to	O
redundant	O
stimuli	O
.	O
</s>
<s>
Research	O
has	O
found	O
an	O
abnormal	O
P50	B-Algorithm
suppression	O
in	O
people	O
with	O
schizophrenia	B-Application
,	O
making	O
it	O
an	O
example	O
of	O
a	O
biological	O
marker	O
for	O
the	O
disorder	O
.	O
</s>
<s>
Besides	O
schizophrenia	B-Application
,	O
abnormal	O
P50	B-Algorithm
suppression	O
has	O
been	O
found	O
in	O
patients	O
with	O
traumatic	O
brain	O
injury	O
,	O
recreational	O
drug	O
use	O
,	O
and	O
post-traumatic	O
stress	O
disorder	O
.	O
</s>
<s>
The	O
second	O
sound	O
is	O
considered	O
redundant	O
,	O
and	O
so	O
a	O
typical	O
control	O
showing	O
normal	O
sensory	O
gating	O
will	O
produce	O
a	O
reduced	O
response	O
(	O
in	O
wave	O
amplitude	B-Application
)	O
to	O
the	O
second	O
click	O
.	O
</s>
<s>
The	O
suppression	O
is	O
measured	O
as	O
the	O
percentage	O
of	O
amplitude	B-Application
decrease	O
in	O
response	O
to	O
the	O
second	O
click	O
compared	O
to	O
the	O
first	O
click	O
,	O
with	O
typical	O
controls	O
showing	O
an	O
approximately	O
80%	O
decrease	O
to	O
the	O
second	O
stimulus	O
.	O
</s>
<s>
Healthy	O
infants	O
as	O
young	O
as	O
1	O
to	O
4	O
months	O
old	O
were	O
found	O
to	O
demonstrate	O
a	O
P50	B-Algorithm
suppression	O
in	O
a	O
paired	O
click	O
task	O
,	O
suggesting	O
that	O
sensory	O
gating	O
is	O
present	O
early	O
in	O
development	O
.	O
</s>
<s>
Studies	O
have	O
found	O
that	O
patients	O
with	O
schizophrenia	B-Application
fail	O
to	O
show	O
a	O
reduced	O
response	O
to	O
the	O
second	O
click	O
.	O
</s>
<s>
Abnormal	O
sensory	O
gating	O
may	O
be	O
behind	O
symptoms	O
of	O
schizophrenia	B-Application
such	O
as	O
sensory	O
overload	O
and	O
difficulty	O
concentrating	O
.	O
</s>
<s>
A	O
link	O
exists	O
between	O
abnormal	O
α7	O
receptors	O
and	O
the	O
abnormal	O
P50	B-Algorithm
response	O
.	O
</s>
<s>
In	O
a	O
family	O
that	O
has	O
a	O
child	O
with	O
schizophrenia	B-Application
,	O
at	O
least	O
one	O
of	O
the	O
parents	O
tends	O
to	O
show	O
higher	O
rates	O
of	O
abnormal	O
P50	B-Algorithm
gating	O
compared	O
to	O
normal	O
controls	O
even	O
when	O
the	O
parents	O
themselves	O
do	O
not	O
have	O
schizophrenia	B-Application
.	O
</s>
<s>
Abnormal	O
P50	B-Algorithm
suppression	O
in	O
paired	O
click	O
tests	O
can	O
be	O
found	O
through	O
either	O
a	O
failure	O
to	O
suppress	O
the	O
second	O
stimulus	O
,	O
or	O
as	O
a	O
failure	O
to	O
produce	O
a	O
heightened	O
response	O
to	O
the	O
first	O
stimulus	O
.	O
</s>
<s>
Some	O
studies	O
suggest	O
that	O
P50	B-Algorithm
suppression	O
in	O
people	O
with	O
schizophrenia	B-Application
might	O
instead	O
appear	O
as	O
a	O
smaller	O
response	O
to	O
the	O
first	O
auditory	O
stimulus	O
.	O
</s>
