<s>
Psychophysics	O
Toolbox	O
Version	O
3	O
(	O
PTB-3	O
)	O
is	O
a	O
collection	O
of	O
free	O
functions	O
for	O
MATLAB	B-Language
or	O
GNU	B-Language
Octave	I-Language
intended	O
for	O
use	O
by	O
neuroscience	O
and	O
vision	O
researchers	O
.	O
</s>
<s>
PTB-3	O
is	O
based	O
on	O
the	O
Psychophysics	O
Toolbox	O
Version	O
2	O
(	O
PTB-2	O
)	O
but	O
its	O
MATLAB	B-Language
extensions	O
(	O
in	O
C	O
)	O
were	O
rewritten	O
to	O
be	O
more	O
modular	O
and	O
use	O
OpenGL	O
.	O
</s>
<s>
Psychtoolbox	O
is	O
offered	O
alongside	O
many	O
alternative	O
toolboxes	O
for	O
programming	O
Psychophysics	O
and	O
Psychology	O
experiments	O
,	O
such	O
as	O
PsychoPy	B-Library
for	O
Python	O
or	O
jsPsych	O
for	O
JavaScript	B-Language
.	O
</s>
<s>
Psychophysics	O
Toolbox	O
Version	O
3	O
is	O
free	B-Application
software	I-Application
.	O
</s>
<s>
Most	O
of	O
it	O
is	O
released	O
under	O
the	B-License
MIT	I-License
License	I-License
,	O
but	O
parts	O
of	O
it	O
are	O
licensed	O
under	O
other	O
open	O
source	O
and	O
free	B-Application
software	I-Application
licenses	O
.	O
</s>
