Figure 6.

Superficial layer field theta bursts are most evident in excitatory synaptic inputs to layer 2/3 RS neurons. A, Example LFP from layer 2 with corresponding power spectrum showing both theta and delta peaks. B, Example of superficial layer RS neuron behavior. RS neurons were defined by their spike response to 0.2 nA, 200 ms depolarizing step. These neurons fired sparsely (<1 spike per delta period on average) but received robust compound EPSPs with clear double peaks (middle, red, trace). In contrast, IPSPs received by these cells did not show double peaks (bottom trace). C, LTS neurons in layer 2 generated variable (1–10) spike numbers on each delta period and received weak, single maximum, compound EPSPs. D, In contrast, superficial layer FS neurons generated more spikes per delta period (3–20) and had EPSP inputs that sometime displayed double peaks. Calibration: 0.1 mV (field), 15 mV (spike traces), 5 mV (postsynaptic potentials), 0.5 s.