Abstract: To explore the extracellular recordings of single unit in the deep brain regions of awake mice, we recorded the neural activity of dorsal cochlear nucleus in awake head-fixed mice using glass micropipettes, and compared with that using brain-slice patch-clamp recordings. The extracellular single-cell recording results showed that principal neurons in dorsal cochlear nucleus were identified: fusiform cells showed spontaneous spike discharge activity at resting potential, “V” shape of sound-induced response frequency tuning curve(FTC), buildup response of post-stimulus time histogram (PSTH), and selectively response to sound vocalizations. Consistent with the results obtained using brain-slice patch-clamp recordings, fusiform cells identified by this extracellular single-unit recording showed spontaneous discharge activity. The neural activity of fusiform cells at rest was different from those of two classes of interneurons in the dorsal cochlear nucleus: cartwheel cells fired spontaneously a burst of spikes at rest; vertical cells remained silent at rest. Therefore, this study suggested that this extracellular single unit recording could be used to identify different cell types in deep brain regions in vivo.

Key words: single-unit extracellular recording, dorsal cochlear nucleus, awake mouse, spontaneous spike activity, cell type