Automatic control of stimulation

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Automatic control of stimulation

Post  mcs on Thu Jun 12, 2008 2:36 am

How can I automatically set a repeating stimulus to stop when a defined response is detected?

I'm trying to repeat the experiments of Shahaf and Marom (2001). To do this I need to stimulate (e.g. with 1 Hz pulses) a cortical culture and monitor the rate of response in a selected electrode(within 50ms of the stimulation) so that when the frequency of response increases (e.g. from less than one response in ten stimuli to 2 or more responses in 10 stimuli) the stimulation is stopped, rested for five minutes and started again.
Specifically, I don't know how to stop the stimulus when the frequency threshold is reached.

I'm using STG 1008 with MCstimulus to control the stimulation.

Many thanks

Rob

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Re: Automatic control of stimulation

Post  mcs on Thu Jun 12, 2008 2:37 am

Dear Rob,

you can connect the Sync Out output of the STG to the digital input of the MC_Card. Insert a trigger detector into your rack and select the digital channel as input channel (for details refer to 'Using the digital data stream for triggering' of the MC_Rack online help). Now you can insert an analyzer into your rack and trigger the analyzer with the Sync Out output of the STG. This means that you can determine the time during which data is analyzed with the Synch Out signal and the ROI settings of the analyzer (see the chapter 'Analyzing Data' of the MC_Rack online help). If the analyzer delivers for example spike rates as output you can insert a second trigger detector which produces a trigger event when the spike rate exceeds a certain value (see 'Using a raw data or a parameter stream for triggering'). Insert the Digital Out instrument into your rack and select this last trigger as input (see the chapter 'Digital Output' of the MC_Rack online help). You will get a pulse at the digital output port of MC_Card each time the spike rate exceeds the chosen value. Note that there is a typical internal delay between the trigger event and the TTL pulse of about 300 ms.
You can connect this bit of the digital output port of MC_Card with the Trig In input of the STG. The Trig In input starts or stops the STG (see 'Triggering Stimulation' of MC_Stimulus online help). Note that you need a DigOut connector for your computer and the MC_Card driver version 2.5 or higher.

best regards
Gerald

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How can I make a DigOut Connector

Post  brooks on Sat Jun 13, 2009 1:38 am

mcs wrote:Dear Rob,

you can connect the Sync Out output of the STG to the digital input of the MC_Card. Insert a trigger detector into your rack and select the digital channel as input channel (for details refer to 'Using the digital data stream for triggering' of the MC_Rack online help). Now you can insert an analyzer into your rack and trigger the analyzer with the Sync Out output of the STG. This means that you can determine the time during which data is analyzed with the Synch Out signal and the ROI settings of the analyzer (see the chapter 'Analyzing Data' of the MC_Rack online help). If the analyzer delivers for example spike rates as output you can insert a second trigger detector which produces a trigger event when the spike rate exceeds a certain value (see 'Using a raw data or a parameter stream for triggering'). Insert the Digital Out instrument into your rack and select this last trigger as input (see the chapter 'Digital Output' of the MC_Rack online help). You will get a pulse at the digital output port of MC_Card each time the spike rate exceeds the chosen value. Note that there is a typical internal delay between the trigger event and the TTL pulse of about 300 ms.
You can connect this bit of the digital output port of MC_Card with the Trig In input of the STG. The Trig In input starts or stops the STG (see 'Triggering Stimulation' of MC_Stimulus online help). Note that you need a DigOut connector for your computer and the MC_Card driver version 2.5 or higher.

best regards
Gerald

Thank you for your advice, would you please provide more information about making the DigOut connector? Thanks.

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How can I connect the Digital In/Out Extension with STG

Post  brooks on Mon Jun 15, 2009 6:22 pm

We have a digital in/out extension with the MC_Card. But I don't know how to connect the 68-pin connector with the BNC socket in STG.

I guess that, the coaxial line will be connected with a BNC socket in one end, and with one of the digital channel in the other end. However, what about the signal ground(GNDS), power ground(GNDP) and pin 67,68. Should I just leave them alone?

Thank you.

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Is that OK?

Post  brooks on Mon Jun 15, 2009 9:57 pm

brooks wrote:We have a digital in/out extension with the MC_Card. But I don't know how to connect the 68-pin connector with the BNC socket in STG.

I guess that, the coaxial line will be connected with a BNC socket in one end, and with one of the digital channel in the other end. However, what about the signal ground(GNDS), power ground(GNDP) and pin 67,68. Should I just leave them alone?

Thank you.

Is the following design correct?


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Re: Automatic control of stimulation

Post  ThomasMCS on Mon Jun 15, 2009 11:46 pm

Assuming all settings in all the involved softwares are set correctly this looks good to me (did not doublecheck the pin numbers however, I guess you just took them from the datasheet...)

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Thank you.

Post  brooks on Tue Jun 16, 2009 12:22 am

ThomasMCS wrote:Assuming all settings in all the involved softwares are set correctly this looks good to me (did not doublecheck the pin numbers however, I guess you just took them from the datasheet...)


Thank you!

I'll try to connect the devices as below. A little concern is that, as we have purchased the dedicated system from MCS several years ago (as early as 2003), our printed user manual come with the system does not agree with the latest online version. Our "outdated" version said that the "Digital output (not supported; please do not connect)". Is it okay for me to ignore this warning?

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Re: Automatic control of stimulation

Post  ThomasMCS on Tue Jun 16, 2009 1:20 am

It seems you have not connected the D i/o.
http://www.multichannelsystems.com/products-mea/product-details/products/127/dio.html

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Re: Automatic control of stimulation

Post  brooks on Tue Jun 16, 2009 3:53 am

[quote="ThomasMCS"]It seems you have not connected the D i/o.
http://www.multichannelsystems.com/products-mea/product-details/products/127/dio.html[/quote]

Shocked . Oh, we don't have this. Maybe I can persuade our "decision-maker" to buy one. Smile
I'll contact Ryan Huang for the price.


Thank you! (If I failed to get one, is there anything important I should pay attention to when making the printed circuit?)

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Re: Automatic control of stimulation

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