As with the experimental data, we find that, in both the current-based and conductance-based models, higher amplitude synapses are easier to detect and there is an asymmetry between excitatory and inhibitory inputs with inhibitory inputs being more difficult to detect than excitatory inputs of the same magnitude.

We used a presynaptic population consisting of the equal number of excitatory and inhibitory neurons, with log-normal distribution of synaptic amplitudes (same distribution, positive weights for excitatory, negative weights for inhibitory), and PSC kernels consisted of the same difference of two exponentials with time constants of 0.5ms and 5ms.

This paradigm for injection of fully-defined current allows us to examine the detectability of excitatory and inhibitory inputs of multiple amplitudes using the same recording [40].

2) Fully-defined current was produced by the firing of a large population of simulated presynaptic excitatory and inhibitory neurons whose postsynaptic currents (PSCs) sum to mimic fluctuating, naturalistic input.

Excitatory and inhibitory inputs are assumed to have the same distribution, differing only by the sign.

The fully-defined input is composed of excitatory and inhibitory postsynaptic currents produced by firing of large number of simulated presyn-aptic neurons.

We ask how well synaptic inputs of different amplitudes can be detected, how much data is necessary to reconstruct the amplitudes of excitatory and inhibitory synaptic inputs, and how precisely synaptic weights can be estimated from spikes alone.

Because spike times of all N = 1024 excitatory and inhibitory presynaptic neurons composing the total input to the postsynaptic neuron (Fig.

The coupling coefficients accurately reconstruct both excitatory and inhibitory input amplitudes over a broad range, and this reconstruction becomes more accurate with higher postsynaptic firing rates (Fig.

To modify the synaptic inputs for changing conductances we split the inputs into excitatory and inhibitory contributions with two separate reversal potentials ry and inhibitory contributions.

For the conductance-based models, since we want the average PSC for each presynaptic input to match the original inputs, we introduce an additional constraint that the excitatory and inhibitory input be balanced: 611 < V(t) — VI > = — < V(t) — VE > aE.