# mWorks: making a circular white noise stimulus

**URL:** <https://mworks.discourse.group/t/mworks-making-a-circular-white-noise-stimulus/275>\
**Category:** Support\
**Created:** [February 26, 2019, 2:29pm UTC](https://mworks.discourse.group/t/mworks-making-a-circular-white-noise-stimulus/275 "2019-02-26T14:29:16Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![cstawarz](https://yyz1.discourse-cdn.com/flex031/user_avatar/mworks.discourse.group/cstawarz/32/3_2.png) [@cstawarz](https://mworks.discourse.group/u/cstawarz)\
**Post date:** [February 26, 2019, 2:29pm UTC](https://mworks.discourse.group/t/mworks-making-a-circular-white-noise-stimulus/275/1 "2019-02-26T14:29:16Z")

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Hi Chris,

I’m trying to make a circular white noise stimulus at a certain location on the screen (I want to use it to mask a grating stimulus and then have subjects determine if the grating was there or not). Is the best way to do this to use the full screen white noise and then put a mask over it that covers up everything except the circle? And then I would put a grating stimulus on top of it with different levels of transparency.

Just wondering your thoughts,

Thanks,

Alex

Alexandra Ferguson  
MIT BCS | Jazayeri Lab

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**Author:** ![cstawarz](https://yyz1.discourse-cdn.com/flex031/user_avatar/mworks.discourse.group/cstawarz/32/3_2.png) [@cstawarz](https://mworks.discourse.group/u/cstawarz)\
**Post date:** [February 26, 2019, 2:54pm UTC](https://mworks.discourse.group/t/mworks-making-a-circular-white-noise-stimulus/275/2 "2019-02-26T14:54:01Z")

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Hi Alex,

> Is the best way to do this to use the full screen white noise and then put a mask over it that covers up everything except the circle? And then I would put a grating stimulus on top of it with different levels of transparency.

Yes, that sounds like a good approach. The attached example demonstrates one way to set things up.

Cheers,  
Chris

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**Author:** ![cstawarz](https://yyz1.discourse-cdn.com/flex031/user_avatar/mworks.discourse.group/cstawarz/32/3_2.png) [@cstawarz](https://mworks.discourse.group/u/cstawarz)\
**Post date:** [February 26, 2019, 2:54pm UTC](https://mworks.discourse.group/t/mworks-making-a-circular-white-noise-stimulus/275/3 "2019-02-26T14:54:01Z")

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Attachment: [masked\_noise.mwel.zip](https://mworks.discourse.group/uploads/short-url/xZ1wwIG2sMu5P2cGwweQcv7TuVF.zip) (552 Bytes)

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<div class="post-metadata">

**Author:** ![cstawarz](https://yyz1.discourse-cdn.com/flex031/user_avatar/mworks.discourse.group/cstawarz/32/3_2.png) [@cstawarz](https://mworks.discourse.group/u/cstawarz)\
**Post date:** [July 19, 2022, 8:55pm UTC](https://mworks.discourse.group/t/mworks-making-a-circular-white-noise-stimulus/275/4 "2022-07-19T20:55:03Z")

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