Fig. 3.

A representative example of passive membrane and firing properties of a layer 2 pyramidal neuron of GRS. a Voltage responses to hyperpolarizing and sub-threshold depolarizing current injections (intensity, −200–60 pA, duration, 1 s). b Voltage responses to supra-threshold depolarizing current injections. The current intensity is indicated at the end of each trace. This neuron had a resting membrane potential of −76 mV. Note that onset of the first action potential is substantially delayed from the initiation of the current injection. Inset red trace indicates a representative example of LS firing pattern recorded at 36°C from another GRS L2 neuron. c Current–voltage (I–V) relationship measured 800 ms after the onset of step currents in a. The input resistance of this neuron was 417 MΩ. d Onset latency of the first to nth spikes in response to the various intensities of the step current shown in b. Each symbol represents a different injection current intensity; squares, triangles, inverted triangles, diamonds and circles represent 70, 80, 100, 150 and 200 pA, respectively. e Inter-spike interval between nth to (n + 1)th spike, calculated from the onset latency data. Symbols are the same as those in d