Hello,
We are using your ethoscope and optomotor module for optogenetics experiments, trying to trigger a Chrimson channel by pulsing 620nm LEDs.
However our first tests didn't show the expected results. There doesn't appear to be any difference in behavior between our control groups and our experimental groups.
Looking at the literature, it appears other teams achieved proper Chrimson activation with a similar wavelength, but much higher light intensity : we measured between 6 and 9 W/m2 at the end of the optic fibers, while we could mostly find values of at least 50 W/m2 in the literature. According to Klapoetke, Murata, Kim et al. "Independent optical excitation of distinct neural populations" (2014), who first described Chrimson, an intensity of at least 15W/m2 seems to be necessary to activate the channel.
As a result, we assume the intensity currently being delivered to our flies is too low to activate the channel. Is it possible to increase the light intensity emitted by the LEDs, and if yes, how should we proceed ?
We also would like to deliver shorter, more frequent pulses. At the moment, our interval parameter is set at 1s and our pulse duration at 700ms. We can't set the interval lower, and while we could go down to 500ms pulse duration, from our testing, it seems the pulses start being very unstable and become unsynchronized quickly. Is it possible to achieve lower pulse duration with higher frequency or is it limited by the hardware ?
Hello,
We are using your ethoscope and optomotor module for optogenetics experiments, trying to trigger a Chrimson channel by pulsing 620nm LEDs.
However our first tests didn't show the expected results. There doesn't appear to be any difference in behavior between our control groups and our experimental groups.
Looking at the literature, it appears other teams achieved proper Chrimson activation with a similar wavelength, but much higher light intensity : we measured between 6 and 9 W/m2 at the end of the optic fibers, while we could mostly find values of at least 50 W/m2 in the literature. According to Klapoetke, Murata, Kim et al. "Independent optical excitation of distinct neural populations" (2014), who first described Chrimson, an intensity of at least 15W/m2 seems to be necessary to activate the channel.
As a result, we assume the intensity currently being delivered to our flies is too low to activate the channel. Is it possible to increase the light intensity emitted by the LEDs, and if yes, how should we proceed ?
We also would like to deliver shorter, more frequent pulses. At the moment, our interval parameter is set at 1s and our pulse duration at 700ms. We can't set the interval lower, and while we could go down to 500ms pulse duration, from our testing, it seems the pulses start being very unstable and become unsynchronized quickly. Is it possible to achieve lower pulse duration with higher frequency or is it limited by the hardware ?