New techniques for making whole-cell recordings from CNS neurons in vivo

Patch-type pipettes increasingly are being used to obtain intracellular 'whole-cell' recordings from neurons. Here we describe our methods for making whole-cell recordings in vivo from midbrain neurons in an electric fish. Novel elements in the procedure are: A device for micropositioning the pipette when near a cell, use of a 'Picospritzer' for cleaning the pipette tip and cell surface, and an electroporetic method for perforating the patch following seal formation. In addition, we show that extracellular and intracellular recordings can be made from the same neuron. Stable intracellular recordings can be made from neurons at least as small as 10 μm.