Optogenetic Stimulation and Electrophysiological Recording of Synaptic Events in Rat Brain Slices

Begin with a rat brain slice containing the target neuron region connected with a light-sensitive axon from a different brain region.

Place the slice into the submerged recording chamber and secure it with a slice anchor.

Under a microscope, locate the desired layer and identify the target pyramidal neuron.

Raise the microscope objective to create a meniscus with the slice surface.

Lower a glass micropipette filled with intracellular recording solution into this meniscus.

Touch the identified pyramidal cell with the pipette tip to create an indent in the membrane.

Apply suction to form a seal.

Increase the suction until the membrane ruptures, establishing a whole-cell configuration.

Using a mounted light source, apply light pulses to the slice.

These light pulses trigger an action potential in the light-sensitive axon, releasing neurotransmitters at the synaptic cleft.

Record the pyramidal neuron's responses to these releases to analyze synaptic efficiency.

For target cell identification, place the slice into the recording chamber, and immobilize it using a slice anchor. Under low magnification, using infrared illumination, navigate to the LEC layer 5. Then, change to the high magn