Optogenetic stimulation of the motor cortex in ChR2 injected mice

Experimental Background and Technology

Optogenetics is proving to be a powerful tool in neuroscience research. The field is currently moving towards optogenetic stimulation of specific populations of neurons in freely-moving mice. To this end, we have designed an implantable stimulator for mouse applications. The mouse stimulator is the "Implantable Stimulator-Transponder" (IST). The IST is a battery-powered, implantable device designed to power implantable, fiber-coupled light sources for optogenetic stimulation. The IST provides stimulation, command acknowledgements, battery monitoring, and a stimulus synchronizing signal, all by radio control.

Implantable Sensor Transmitter(IST).

The implanatable light sources that can be coupled with the IST are the Surface-Mount Light-Emitting Diode (SMLED), and the Fiber-Coupled Light-Emitting Diode(FCLED).

Surface-Mount Light-Emitting Diode(SMLED).

The Fiber-Coupled Light-Emitting Diode(FCLED) is the SMLED with a tapered fiber placed directly on tothe LED. The fiber is 4mm long, with a diameter of 270um.

Fiber-Coupled Light-Emitting Diode(SMLED).

Experimental Design

In order to validate our technology, we have identified two optogenetic stimulations which should induce distinct behavioral phenotypes.

The first identifiable phenotype is circling behavioral. The second phenotype is seizure like acticity.

In order to induce these distinct behavioral phenotypes, we injected ChR2 into the motor cortex of 6 mice. We then implanted our devices and administered light at varying pulses lengths, frequencies, and durations.

Seizure like behavior induced by optogenetic stimulation of the motor cortex

August 8th, 2021, Animal 6, trial 6: Optogentic stimulus given via a 4mm fiber-coupled blue LED coupled with the wireless IST.

Figure: Intrinsic flourescent image of ChR2 expressing neurons in the right motor cortex of animal 6	Video: Animal 2, behavioral response to 1ms pulses of blue light at 10hz for 90s.

Circling induced by optogenetic stimulation of the motor cortex

August 3rd, 2021, Animal 2, trial 4: Optogentic stimulus given via a 4mm fiber-coupled blue LED coupled with the wireless the IST.

Figure: Intrinsic flourescent image of ChR2 expressing neurons in the right motor cortex of animal 6	Video: Animal 6, behavioral response to 1ms pulses of blue light at 10hz for 90s.