Biological neuron

Hello!

I have a question about neurons “preferred stimulus”. In the documentation, it says some prefer -1 and others prefer +1, thus, they spike for negative and positive values, respectively. However, in what sense does a neuron spike given negative stimulus? Isn’t that like says an inhibitory post synaptic potential causes the post synaptic neuron to spike? Also, given that is the case, with a brief sub-threshold stimulus, there should be no spikes, however, any deviation from the “intercept” causes spiking activity in my ensemble, how does this represent the LIF neuron model?

Is it possible to have the spiking of one neuron cause IPSPs in the neuron which it projects to? In the simplest case, could you have two ensembles, both with a single neuron. Have the neurons themselves connected, where the first neuron is an inhibitory neuron, then spiking activity in the first neuron produces zero spiking in the second neuron, since it is projecting inhibitory neurotransmitters or whatever the representation of that may be in Nengo?

Thanks ^___^