Light Stimulation Plate Demo MWP


Zantiks offer an add-on light plate as an additional bright light source with brightness control. It is useful for optogenetic stimulation, or initiation of a startle response, and comes in a variety of different wavelengths including white, blue, and green (Please contact us to discuss your requirements).

There is a fairly even brightness across the light plate, and we have confirmed that the plate can stimulate zebrafish larvae and adult Drosophila. However, we recommend full validation of stimulation performance in different wells for your test animals.

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Assembling the Light Stimulation Plate


The light plate can incorporate a diffusing stand, and so replaces the standard diffusing stand that is supplied with the MWP_vb unit. The main components include:

  1. Light plate with incorporated diffusing stand
  2. LED holder (with your choice of wavelength lights)
  3. Control circuit to plug directly into the MWP unit
  4. Foam door (with hole for light plate)
Lightsheetbits
The main components of the light stimulation plate.

The system plugs directly into the MWP, and does not require an additional power supply.

Control of the system is from the included Zanscript programming language, and incorporates control of both the brightness of the light and the duration of the stimulus.

The brightness of the light is controlled by the voltage set on output4. This is the 7th connector on the 8-way output located at CN5 of the lower board (see picture).

The light being on or off is controlled by the relay output from CN4, which is the second of the - way connectors on the lower board from the left (see picture).

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Side socket of MWP unit demonstrating how the wires for the light stimulation plate should be connected in CN4 and CN5 of the lower board

The LED holder is then connected to the control circuitry with the push connectors.

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Push plugs connecting LED holder to the control circuit
Led Holder Connect
Connection of the LED holder to the MWP unit via the control circuit

The LED holder can be attached to the light plate. This can then be inserted into the MWP unit with the foam door to prevent any excess light entering or exiting the unit (see images below).

Light Plate On 2
LED holder attached to light plate with green LEDs
Light Plate Door
Light plate with LED holder inserted into MWP unit with foam door to prevent light escaping
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We are using a third party LED driver device which allows us to control the on/off and brightness of the LEDs from the ZANTIKS script and electronics. This allows the system to be fully integrated into the Zantiks experiments.

The LED driver is permanently powered from the 3 way connector plugged in as in the previous photo (CN4). CN4 each provides permanent 12V power, a 12V power source switched by relays controlled from Zanscript, and a ground connection. CN4 has power applied by default, and when power is provided here the plate will not be lit. When power is not applied then the LED will light as controlled by the voltage out from the 4th output of CN5. High voltages (10000 mv) keep the plate unlit, and low voltages (anything below about 4000mv) will have the plate at full power.


Below is the text from the script opto_stim.zs

INCLUDE zsys
 
DEFINE WAIT_TIME_SECS 3
DEFINE NUM_OF_TIMES 10
 
ACTION MAIN
 
 SET(VOLTAGE4,ON)
 SET(VOLTAGE_LEVEL,10000)
 INVOKE(OPTO,NUM_OF_TIMES)
 
COMPLETE
 
 
ACTION OPTO
 
 INVOKE(OPTO_TIMING,1)
 INVOKE(OPTO_BRIGHTNESS,1)
 
COMPLETE
 
 
ACTION OPTO_TIMING
 
 SET(VOLTAGE_LEVEL,2000)
 
 ZCOMMAND("C1#0 P10 C1#1")
 WAIT(WAIT_TIME_SECS)
 
 ZCOMMAND("C1#0 P50 C1#1")
 WAIT(WAIT_TIME_SECS)
 
 ZCOMMAND("C1#0 P250 C1#1")
 WAIT(WAIT_TIME_SECS)
 
COMPLETE
 
 
ACTION OPTO_BRIGHTNESS
 
 ZCOMMAND("C1#0")
 WAIT(WAIT_TIME_SECS)
 
 SET(VOLTAGE_LEVEL,3000)
 WAIT(WAIT_TIME_SECS)
 
 SET(VOLTAGE_LEVEL,4000)
 WAIT(WAIT_TIME_SECS)
 
 SET(VOLTAGE_LEVEL,5000) 
 WAIT(WAIT_TIME_SECS)
 
 SET(VOLTAGE_LEVEL,6000)
 WAIT(WAIT_TIME_SECS)
 
 SET(VOLTAGE_LEVEL,7000)
 WAIT(WAIT_TIME_SECS)
 
 SET(VOLTAGE_LEVEL,8000)
 WAIT(WAIT_TIME_SECS)
 
 SET(VOLTAGE_LEVEL,9000)
 WAIT(WAIT_TIME_SECS)
 
 SET(VOLTAGE_LEVEL,10000)
 WAIT(WAIT_TIME_SECS)
 
COMPLETE


Some key points to understand about this script include:

SET(VOLTAGE4, ON)

enables output of voltage on output 4 of CN5.

SET(VOLTAGE_LEVEL,10000)

sets the voltage at 10000mv, which leads to the plate being off. Lowering the voltage to 2000mv enables the system to be high power and the light will be at full brightness. Gradually increasing the voltage reduces the LED brightness.

ZCOMMAND("C1#0 P10 C1#1")

ZCOMMAND controls the relay and pauses. "C1#0" turns off the override so that the brightness is controlled by the voltage. "P10" delays (or Pauses) for 10ms. "C1#1" turns the override back on, so the plate is unlit. Increasing or decreasing "P" here will increase or decrease the time the light is on i.e. length of light flash.

The script produces a light sequence of flashes at increasing length, followed by a sequence of varying voltage where the LED changes from maximum brightness down to lights off.

Demonstration of the opt_stim.as sample script for the light stimulation plate

Please note: the light stimulation plate can also be operated in the relay output CN3. Unlike CN4, which provides permanent power as a default, resulting in the plate being unlit, the default from CN3 is to provide no power, resulting in the plate being lit.

If you are using the CN3 relay, the above script will work exactly the same, except you will need to edit the ZCOMMAND in the script from "C1" to "C2" in order to control the relay when the connector is in CN3.

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Here you can download the opto_stim script

Please try running it with the system plugged in to see how control can work for both length of stimulus (set by P10, P50 etc.) and for brightness (by varying the control voltage).