<s>
A	O
gamma	B-Algorithm
wave	I-Algorithm
or	O
gamma	B-Algorithm
rhythm	I-Algorithm
is	O
a	O
pattern	O
of	O
neural	B-Algorithm
oscillation	I-Algorithm
in	O
humans	O
with	O
a	O
frequency	O
between	O
25	O
and	O
140	O
Hz	O
,	O
the	O
40	O
Hz	O
point	O
being	O
of	O
particular	O
interest	O
.	O
</s>
<s>
Gamma	B-Algorithm
rhythms	I-Algorithm
are	O
correlated	O
with	O
large	O
scale	O
brain	O
network	O
activity	O
and	O
cognitive	O
phenomena	O
such	O
as	O
working	O
memory	O
,	O
attention	O
,	O
and	O
perceptual	O
grouping	O
,	O
and	O
can	O
be	O
increased	O
in	O
amplitude	O
via	O
meditation	O
or	O
neurostimulation	O
.	O
</s>
<s>
Altered	O
gamma	O
activity	O
has	O
been	O
observed	O
in	O
many	O
mood	O
and	O
cognitive	O
disorders	O
such	O
as	O
Alzheimer	O
's	O
disease	O
,	O
epilepsy	O
,	O
and	O
schizophrenia	B-Application
.	O
</s>
<s>
Gamma	B-Algorithm
waves	I-Algorithm
can	O
be	O
detected	O
by	O
electroencephalography	B-Application
or	O
magnetoencephalography	B-Algorithm
.	O
</s>
<s>
One	O
of	O
the	O
earliest	O
reports	O
of	O
gamma	B-Algorithm
wave	I-Algorithm
activity	O
was	O
recorded	O
from	O
the	O
visual	O
cortex	O
of	O
awake	O
monkeys	O
.	O
</s>
<s>
Gamma	O
activity	O
has	O
also	O
been	O
detected	O
and	O
studied	O
across	O
premotor	O
,	O
parietal	O
,	O
temporal	O
,	O
and	O
frontal	O
cortical	O
regions	O
Gamma	B-Algorithm
waves	I-Algorithm
constitute	O
a	O
common	O
class	O
of	O
oscillatory	O
activity	O
in	O
neurons	O
belonging	O
to	O
the	O
cortico-basal	O
ganglia-thalamo-cortical	O
loop	O
.	O
</s>
<s>
Typically	O
,	O
this	O
activity	O
is	O
understood	O
to	O
reflect	O
feedforward	B-Algorithm
connections	O
between	O
distinct	O
brain	O
regions	O
,	O
in	O
contrast	O
to	O
alpha	O
wave	O
feedback	O
across	O
the	O
same	O
regions	O
.	O
</s>
<s>
Gamma	B-Algorithm
oscillations	I-Algorithm
have	O
also	O
been	O
shown	O
to	O
correlate	O
with	O
the	O
firing	O
of	O
single	O
neurons	O
,	O
mostly	O
inhibitory	O
neurons	O
,	O
during	O
all	O
states	O
of	O
the	O
wake-sleep	O
cycle	O
.	O
</s>
<s>
Gamma	B-Algorithm
wave	I-Algorithm
activity	O
is	O
most	O
prominent	O
during	O
alert	O
,	O
attentive	O
wakefulness	O
.	O
</s>
<s>
Some	O
researchers	O
contest	O
the	O
validity	O
or	O
meaningfulness	O
of	O
gamma	B-Algorithm
wave	I-Algorithm
activity	O
detected	O
by	O
scalp	O
EEG	B-Application
,	O
because	O
the	O
frequency	O
band	O
of	O
gamma	B-Algorithm
waves	I-Algorithm
overlaps	O
with	O
the	O
electromyographic	O
frequency	O
band	O
.	O
</s>
<s>
Studies	O
utilizing	O
local	O
muscle	O
paralysis	O
techniques	O
have	O
confirmed	O
that	O
EEG	B-Application
recordings	O
do	O
contain	O
EMG	O
signal	O
,	O
and	O
these	O
signals	O
can	O
be	O
traced	O
to	O
local	O
motor	O
dynamics	O
such	O
as	O
saccade	O
rate	O
or	O
other	O
motor	O
actions	O
involving	O
the	O
head	O
.	O
</s>
<s>
Advances	O
in	O
signal	O
processing	O
and	O
separation	O
,	O
such	O
as	O
the	O
application	O
of	O
independent	B-Algorithm
component	I-Algorithm
analysis	I-Algorithm
or	O
other	O
techniques	O
based	O
on	O
spatial	O
filtering	O
,	O
have	O
been	O
proposed	O
to	O
reduce	O
the	O
presence	O
of	O
EMG	O
artifacts	O
.	O
</s>
<s>
In	O
at	O
least	O
some	O
EEG	B-Application
textbooks	O
,	O
users	O
are	O
instructed	O
to	O
put	O
an	O
electrode	O
on	O
an	O
eyelid	O
to	O
catch	O
these	O
,	O
as	O
well	O
as	O
1	O
on	O
the	O
heart	O
,	O
&	O
a	O
pair	O
on	O
the	O
sides	O
of	O
the	O
neck	O
,	O
to	O
catch	O
muscle-signal	O
from	O
the	O
body	O
below	O
the	O
neck	O
.	O
</s>
<s>
Clinical	O
EEG	B-Application
may	O
not	O
do	O
these	O
things	O
.	O
</s>
<s>
Gamma	B-Algorithm
waves	I-Algorithm
may	O
participate	O
in	O
the	O
formation	O
of	O
coherent	O
,	O
unified	O
perception	O
,	O
also	O
known	O
as	O
the	O
problem	O
of	O
combination	O
in	O
the	O
binding	O
problem	O
,	O
due	O
to	O
their	O
apparent	O
synchronization	O
of	O
neural	O
firing	O
rates	O
across	O
distinct	O
brain	O
regions	O
.	O
</s>
<s>
40-Hz	O
gamma	B-Algorithm
waves	I-Algorithm
were	O
first	O
suggested	O
to	O
participate	O
in	O
visual	O
consciousness	O
in	O
1988	O
,	O
.e.g	O
,	O
two	O
neurons	O
oscillate	O
synchronously	O
(	O
though	O
they	O
are	O
not	O
directly	O
connected	O
)	O
when	O
a	O
single	O
external	O
object	O
stimulates	O
their	O
respective	O
receptive	O
fields	O
.	O
</s>
<s>
in	O
the	O
journal	O
Consciousness	O
and	O
Cognition	O
(	O
1999	O
)	O
that	O
argues	O
for	O
temporal	O
synchrony	O
as	O
the	O
basis	O
for	O
consciousness	O
,	O
defines	O
the	O
gamma	B-Algorithm
wave	I-Algorithm
hypothesis	O
thus	O
:	O
</s>
<s>
The	O
suggested	O
mechanism	O
is	O
that	O
gamma	B-Algorithm
waves	I-Algorithm
relate	O
to	O
neural	O
consciousness	O
via	O
the	O
mechanism	O
for	O
conscious	O
attention	O
:	O
</s>
<s>
This	O
has	O
led	O
to	O
theories	O
that	O
gamma	B-Algorithm
waves	I-Algorithm
are	O
associated	O
with	O
solving	O
the	O
binding	O
problem	O
.	O
</s>
<s>
Gamma	B-Algorithm
waves	I-Algorithm
are	O
observed	O
as	O
neural	B-Algorithm
synchrony	I-Algorithm
from	O
visual	O
cues	O
in	O
both	O
conscious	O
and	O
subliminal	O
stimuli	O
.	O
</s>
<s>
This	O
research	O
also	O
sheds	O
light	O
on	O
how	O
neural	B-Algorithm
synchrony	I-Algorithm
may	O
explain	O
stochastic	O
resonance	O
in	O
the	O
nervous	O
system	O
.	O
</s>
<s>
Altered	O
gamma	B-Algorithm
wave	I-Algorithm
activity	O
is	O
associated	O
with	O
mood	O
disorders	O
such	O
as	O
major	O
depression	O
or	O
bipolar	O
disorder	O
and	O
may	O
be	O
a	O
potential	O
biomarker	O
to	O
differentiate	O
between	O
unipolar	O
and	O
bipolar	O
disorders	O
.	O
</s>
<s>
Rodent	O
models	O
of	O
depression-like	O
behaviors	O
also	O
exhibit	O
deficient	O
gamma	B-Algorithm
rhythms	I-Algorithm
.	O
</s>
<s>
Decreased	O
gamma-wave	O
activity	O
is	O
observed	O
in	O
schizophrenia	B-Application
.	O
</s>
<s>
Specifically	O
,	O
the	O
amplitude	O
of	O
gamma	B-Algorithm
oscillations	I-Algorithm
is	O
reduced	O
,	O
as	O
is	O
the	O
synchrony	O
of	O
different	O
brain	O
regions	O
involved	O
in	O
tasks	O
such	O
as	O
visual	B-Algorithm
oddball	I-Algorithm
and	O
Gestalt	O
perception	O
.	O
</s>
<s>
People	O
with	O
schizophrenia	B-Application
perform	O
worse	O
on	O
these	O
behavioral	O
tasks	O
,	O
which	O
relate	O
to	O
perception	O
and	O
continuous	O
recognition	O
memory	O
.	O
</s>
<s>
The	O
neurobiological	O
basis	O
of	O
gamma	O
dysfunction	O
in	O
schizophrenia	B-Application
is	O
thought	O
to	O
lie	O
with	O
GABAergic	O
interneurons	O
involved	O
in	O
known	O
brain	B-Algorithm
wave	I-Algorithm
rhythm-generating	O
networks	O
.	O
</s>
<s>
Antipsychotic	O
treatment	O
,	O
which	O
diminishes	O
some	O
behavioral	O
symptoms	O
of	O
schizophrenia	B-Application
,	O
does	O
not	O
restore	O
gamma	O
synchrony	O
to	O
normal	O
levels	O
.	O
</s>
<s>
Gamma	B-Algorithm
oscillations	I-Algorithm
are	O
observed	O
in	O
the	O
majority	O
of	O
seizures	O
and	O
may	O
contribute	O
to	O
their	O
onset	O
in	O
epilepsy	O
.	O
</s>
<s>
Visual	O
stimuli	O
such	O
as	O
large	O
,	O
high-contrast	O
gratings	O
that	O
are	O
known	O
to	O
trigger	O
seizures	O
in	O
photosensitive	O
epilepsy	O
also	O
drive	O
gamma	B-Algorithm
oscillations	I-Algorithm
in	O
visual	O
cortex	O
.	O
</s>
<s>
During	O
a	O
focal	O
seizure	O
event	O
,	O
maximal	O
gamma	B-Algorithm
rhythm	I-Algorithm
synchrony	O
of	O
interneurons	O
is	O
always	O
observed	O
in	O
the	O
seizure	O
onset	O
zone	O
,	O
and	O
synchrony	O
propagates	O
from	O
the	O
onset	O
zone	O
over	O
the	O
whole	O
epileptogenic	O
zone	O
.	O
</s>
<s>
Optogenetic	O
stimulation	O
of	O
fast-spiking	O
interneurons	O
in	O
the	O
gamma	B-Algorithm
wave	I-Algorithm
frequency	O
range	O
was	O
first	O
demonstrated	O
in	O
mice	O
in	O
2009	O
.	O
</s>
<s>
Entrainment	O
or	O
synchronization	O
of	O
hippocampal	O
gamma	B-Algorithm
oscillations	I-Algorithm
and	O
spiking	O
to	O
40Hz	O
via	O
non-invasive	O
stimuli	O
in	O
the	O
gamma	O
frequency	O
band	O
,	O
such	O
as	O
flashing	O
lights	O
or	O
pulses	O
of	O
sound	O
,	O
reduces	O
amyloid	O
beta	O
load	O
and	O
activates	O
microglia	O
in	O
the	O
well-established	O
5XFAD	O
mouse	O
model	O
of	O
AD	O
.	O
</s>
<s>
Hypersensitivity	O
and	O
memory	O
deficits	O
in	O
Fragile	O
X	O
syndrome	O
may	O
be	O
linked	O
to	O
gamma	B-Algorithm
rhythm	I-Algorithm
abnormalities	O
in	O
sensory	O
cortex	O
and	O
hippocampus	O
.	O
</s>
<s>
For	O
example	O
,	O
decreased	O
synchrony	O
of	O
gamma	B-Algorithm
oscillations	I-Algorithm
has	O
been	O
observed	O
in	O
auditory	O
cortex	O
of	O
FXS	O
patients	O
.	O
</s>
<s>
The	O
FMR1	O
knockout	O
rat	O
model	O
of	O
FXS	O
exhibits	O
an	O
increased	O
ratio	O
of	O
slow	O
(	O
~	O
25-50Hz	O
)	O
to	O
fast	O
(	O
~	O
55-100Hz	O
)	O
gamma	B-Algorithm
waves	I-Algorithm
.	O
</s>
<s>
High-amplitude	O
gamma	B-Algorithm
wave	I-Algorithm
synchrony	O
can	O
be	O
self-induced	O
via	O
meditation	O
.	O
</s>
<s>
Long-term	O
practitioners	O
of	O
meditation	O
such	O
as	O
Tibetan	O
Buddhist	O
monks	O
exhibit	O
both	O
increased	O
gamma-band	O
activity	O
at	O
baseline	O
as	O
well	O
as	O
significant	O
increases	O
in	O
gamma	O
synchrony	O
during	O
meditation	O
,	O
as	O
determined	O
by	O
scalp	O
EEG	B-Application
.	O
</s>
