Figure 2.

Model exploration: replication of pyramidal cells properties when stimulated locally (no feedback) and constraints imposed on the model during global stimulation (with feedback). A, Schematic of the main components of the model: an LIF model cell receiving feedforward input from the receptors and feedback inputs from the EGp. A DAP was added to replicate the neuron's burst propensity. The feedback inputs have a direct excitatory component delivered through plastic synapses (of weight w) and a disynaptic nonplastic inhibitory component. This feedback input is active only when modeling the response to global stimuli. B, Peristimulus time histograms comparing the response of in vivo (n = 9 cells) and modeled pyramidal cells elicited by local stimuli of different AM frequencies. Dashed lines represent the average firing rate. C, Interspike interval histograms of the model's responses and for experimental data (n = 9 cells) for AM rates ranging from 0.5 to 32 Hz. Bin width is 4 ms. Although ISIs >200 ms do occur, they are rare, and the histogram's area is normalized to 1 for ISIs <200 ms. D, Comparison of in vivo and modeled pyramidal cell responses (n = 9 cells) during local stimulation: burst rates as a function of stimulus frequency. Bursting is quantified by dividing the spike trains into small (2 or 3 spikes) or large bursts (4 or 5 spikes); longer bursts are taken as combinations of small and large bursts (see Materials and Methods).