Figure 4.

Chronic cranial window with access port for electrophysiology. While metal electrodes and beveled electrodes for single or multi-unit recording can simply penetrate the silicone plug, in our hands, it was necessary to remove the plug for patch clamp experiments to reach a high success rate (A). A GFP-expressing layer 2/3 pyramidal neuron shown in x-z plane projection (B) and x-y plane projection (C) was targeted for whole-cell patch clamp recording under anesthesia (1% isoflurane) (D) and filled with a red fluorescent dye after plug removal. The access port does not affect the imaging quality as shown by in vivo imaging of GFP-expressing neurons in layer 5 of barrel cortex after viral gene transfer (E).