A rapid time constant in dual patch single astrocyte recording. (a, b) Whole-cell current profiles of two interneurons recorded from CA1 stratum radiatum. (a1, b1) To resolve the time constant (τ) of VC induced VM in dual patch recording, a -40 mV voltage pulse was applied through E1 and the induced VM was recorded from E2. (a2, b2) The downward rise phase of VMs (from the grey shadows in a1, b1) were fitted with mono-exponential model to resolve the τ values, which varied considerably between a2 and b2. (c) A representative -40 mV voltage pulse induced VM from dual patch astrocyte recording (c1) and the resolved τ value (c2). (d) Summary of the τ values from interneurons and astrocytes, indicating a significantly faster τ value in astrocyte compared to that of the neurons in dual patch recording.