Optical Recording of Neuronal Activity in Brain Slices Stained with a Voltage-Sensitive Dye

Take an immobilized mouse brain slice stained with a voltage-sensitive dye or VSD, fluorescent molecules that integrate into the neuronal membrane and respond to membrane potential changes.

Place the slice in a recording chamber.

Install the ground electrode for a baseline voltage reference.

Next, position the stimulating and recording electrodes on the slice.

Apply an electrical pulse.

The pulse stimulates the neurons, triggering voltage-gated sodium channel opening and sodium ion influx, leading to a membrane potential change.

This induces an action potential, measured by the recording electrode, and alters the VSD's fluorescent properties.

Expose the brain slice to a specific wavelength to excite the VSD and trigger fluorescence emission.

Post-stimulation, the sodium channels close while the voltage-gated potassium channels open, promoting potassium ion efflux.

This changes the membrane potential again and consequently alters the VSD's fluorescence.

Record the fluorescence in real-time to visually represent neuronal activity.