In Vivo Recording of Intracellular Signals from a Single Neuron

Begin with a glass micropipette and fill it with an ionic solution.

Attach the prepared micropipette to a holder with a connector wire. The holder is secured in a micromanipulator.

The setup is connected to an intracellular amplifier, which converts ionic signals within the neuron into readable electrical outputs.

Place a reference electrode on the neck muscles of an anesthetized rat with its skull exposed.

Insert the micropipette into the target brain region. This results in a voltage change. Rectify this change using the amplifier.

Remove any moisture at the site and seal the opening with a sealing agent to minimize brain movements.

Gradually lower the micropipette until a significant increase in resistance is observed, indicating contact of the micropipette with the membrane of a neuron.

Use a transient electrical pulse to disrupt the membrane, creating a temporary opening for micropipette penetration.

Record the electrical signals from within the neuron.

In this step, pull a glass micropipette with a 0.2-micrometer tip and fill it with two molar potassium acetate solution. Place the pipette in a specific holder with a silver-silver chloride wire to connect the pipette solution to an intracellular amplifier. Then, place a silver-silver chloride reference electrode on the rat's neck muscles. Place the pipette above the region of interest.

Slowly, insert the pipette into the brain, down to the desired depth, using the buzz button of the amplifier to clear the pipette if needed. Next, use cotton swabs or synthetic absorption triangles to dry the craniotomy, and cover it with silicone elastomer, or 4% agarose, to reduce brain movements.

Afterward, lower the pipette in one- or two-micrometer steps until its resistance increases when approaching a cell. Use the buzz function of the amplifier to penetrate into the neuron.