# Trouble with drifting grating

**URL:** <https://mworks.discourse.group/t/trouble-with-drifting-grating/428>\
**Category:** Support\
**Created:** [December 7, 2016, 3:41pm UTC](https://mworks.discourse.group/t/trouble-with-drifting-grating/428 "2016-12-07T15:41:24Z")\
**Posts on this page:** 5\
**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:** [December 7, 2016, 3:41pm UTC](https://mworks.discourse.group/t/trouble-with-drifting-grating/428/1 "2016-12-07T15:41:24Z")

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I’m trying to use the standard drifting grating stimulus to show static gratings that vary in orientation, spatial frequency, and contrast. When I run the program no grating is actually shown. I’m sure there’s something silly that I’m missing, but cannot for the life of me figure it out. The xml is attached.

Thank you,  
Brittany

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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:** [December 7, 2016, 3:41pm UTC](https://mworks.discourse.group/t/trouble-with-drifting-grating/428/2 "2016-12-07T15:41:24Z")

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Attachment: [RSVP\_Gratings\_con\_sf2.xml](https://mworks.discourse.group/uploads/short-url/mtI05eBCii9MjqYHD4I5BhULl7W.xml) (60.1 KB)

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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:** [December 7, 2016, 4:27pm UTC](https://mworks.discourse.group/t/trouble-with-drifting-grating/428/3 "2016-12-07T16:27:41Z")

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Hi Brittany,

You need to either

1. Set the grating’s [autoplay](http://mworks-project.org/documentation/0.7/components/drifting_grating_stimulus.html#autoplay) parameter to 1, or
2. Explicitly start and stop the grating using [Play Dynamic Stimulus](http://mworks-project.org/documentation/0.7/components/play_dynamic_stimulus.html) and [Stop Dynamic Stimulus](http://mworks-project.org/documentation/0.7/components/stop_dynamic_stimulus.html).

That should fix it. If not, please let me know!

Chris

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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:** [December 7, 2016, 4:44pm UTC](https://mworks.discourse.group/t/trouble-with-drifting-grating/428/4 "2016-12-07T16:44:46Z")

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Oh my goodness, so simple! Thank you. If it doesn’t work I will let you  
know. I’ll test it out when the rig is free.

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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:** [July 19, 2022, 10:00pm UTC](https://mworks.discourse.group/t/trouble-with-drifting-grating/428/5 "2022-07-19T22:00:28Z")

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