A TECHNIQUE FOR CONTROLLING THE MEMBRANE-POTENTIAL OF NEURONS DURING UNIT RECORDING

While extracelluar unit recordings are technically easier to perform than intracellular recordings, the latter permits control of neuron excitability by changing the membrane potential with steady current passed across the recording micropipette. Utilizing an intracellular amplifier with bridge circuit for the passage of low current (1-10 nA), we show that an extracelluar recording micropipette of high resistance (5-20 MΩ) can be used in a similar fashion while monitoring single unit activity in the rat brain. This procedure allows fine control of two neuronal mechanisms which are voltage-sensitive: action potential discharge and regenerative bursting. Control of a neuron's membrane potential expands the capabilities of unit recording in the study of evoked synaptic input and bursting behaviour. It can also facilitate classification of neurons based on their firing characteristics. © 1990.