Fig. 2. (A) Extracellular recordings of action potentials from CNSS. Dahlgren cell shows a triphasic, long-duration (ca. 8 ms) action potential waveform. An unidentified cell type, neuron, generates a short duration (<1 ms) action potential. (B) Multiunit extracellular recording (i) of spontaneously firing Dahlgren cells in SWA CNSS, analysed off-line using Spike2 to distinguish activity (action potentials displayed by the software as event marks) in four separate units (ii-v). Three different firing patterns are seen: tonic (ii), phasic (iii) and bursting activity (iv,v). (C) Intracellular recordings from three type 1 Dahlgren cells, illustrating spontaneous tonic (i), phasic (ii) and bursting activity patterns (iii).